i have a page on which i have some rating function like people who like the post can rate up or who don't can rate down.
on that link im calling a php file with some parameters passed in the anchor tag. Then in that php file im saving that rating with +1 or -1 (whichever is the case) in the database and after doing that im redirecting to that first page from where we have rated.
Now this whole function is reloading my whole page which i dont want.Is there any way with which i can do this rating without reloading the page,i want that when a person clicks on rate then just after click the rating should be shown according to what the user just did(+ or -) and that too without reloading the whole page.Is there any way to do that in php???????
Yes, it's called "Ajax". However, you don't do this on the server-side with PHP, you do it on the client-side with JavaScript. There are plenty of tutorials around, I suggest you take a look.
Note that there are many JavaScript libraries out there to make this extremely easy. I'd recommend taking a look at jQuery because I've personally found it to be the easiest to learn and use.
It seems a few answers have already been posted recommending different libraries. If you would like the avoid the (admittedly minimal) overhead of an included library, the following tutorial shows how to use a simple XMLHttpRequest object.
http://www.xul.fr/en-xml-ajax.html
The "xhr.responseText" is what you would receive back from the php processing (which would typically be done in a small, single-purpose script seperate from the primary page).
You can do this using Javascript or AJAX. There are plenty of free scripts online that can help you to do this without building the whole thing from scratch.
This page (http://www.ajaxprojects.com/ajax/tutorialdetails.php?itemid=364) has a good list of different star rating scripts you can choose from. You can Google for more.
Here's another relevant tutorial I came across when answering some other question:
http://docs.jquery.com/Tutorials:Getting%5FStarted%5Fwith%5FjQuery#Rate%5Fme:%5FUsing%5FAjax
Related
Looking at other questions, none seem to be specific enough for my case. I am creating a blog-like website and have created a user-authenticated page that allows me to add a title, main content, and image using a form that is sent to a php file that stores the data in the mySQL database. Then, the php redirects me to the index page where I want to load the latest blog post along with all previous posts and put them in a div with styling. I do not think I need AJAX for this. I only need the data to load per each visit, therefore, is the best thing for me to do is to call a javascript function on $(document).ready() that will access the data in the database? If so, how can I implement PHP in my javascript to work with the database and then store the info in javascript variables.
Thanks
You certainly don't need AJAX for this. Just use your index.php page to look up the blog posts in the db and then loop through and echo them out.
You could later incorporate AJAX to call a php page which would provide the blog posts to you. This way you could update the page after it is loaded when new blog posts are created.
Hope that helps.
Clearly you do not seem to have a firm grasp on the role of each language. If you're building something on your own follow the advice of someone who has built ALL of it and can show it off to boot (see my profile, my site contains a blog, forums, private messaging, chat room, CMS, etc all built entirely by myself using no one else's code).
(X)HTML - It's the noun language, an image, a paragraph, a division element used by CSS to style the page, etc.
CSS - The adjective language, describes how the (X)HTML noun language is displayed.
JavaScript - The verb language, event driven; when the user does (onmouseover, onclick, onload, etc) action execute this code (usually a function). AJAX is simply loading content after the page has finished loading. You can worry about the fancy stuff once you have your basics working.
PHP - Server side language, prepares code (mostly XHTML) to be sent to the client's computer.
Database - Where your content is stored.
"$(document).ready() " is not JavaScript, that's jQuery. If you want to learn stay as far away from JavaScript libraries and learn REAL JavaScript otherwise you're going to run in to the nightmares associated with it (crap performance versus native JavaScript, updating libraries changes how you must code to them, etc). Feel free to look at my site's source code as it's all written for XHTML as application/xhtml+xml which means it WILL work in regular HTML though the vast majority of sites do NOT work if you switch them to XHTML. In other words when you code right the first time you'll have much more confidence that it will JUST WORK end of story. People don't care about how you did it but that it works and if it ALWAYS works then they simply can't get any happier with what they have.
If you're building the main blog page you simply need a single SQL query to pull all the content. My blog I programmed to display the last eight latest blog entries though with my pagination it's exactly like a book, the first page (on the left side) starts with the first eight, so if the count isn't divisible by eight you might see six entries on the latest page.
When using SQL you want to CONSTRUCT your query, NEVER stick it inside of a loop! The fewer queries you execute the better your code is and the better your performance. I recommend downloading MySQL Workbench and setting up a MySQL query log and then use Tail for Win32 to view queries in real time to see what your code is doing.
Apache also has logs. You are building this LOCALLY at http:// localhost/ first correct? You should never test something live until you've exhausted testing it locally first. See my base element blog entry about how to best do that...
http://www.jabcreations.com/blog/streamlining-local-and-live-development-with-the-base-element
If you're talking about redirects keep the technical stuff hidden from users and take advantage of $_SESSIONS in PHP. Record what the current page URL is (relative to the base which is different for local/local network/live environments), have a second-URL to fall back to and if that too matches the redirect page then have a safe-URL that is statically defined. If you're constantly falling back to the static URL then check to make sure you haven't goofed up how your other two variables are being updated each page load (such as not updating it if you're on the redirect page obviously).
When you solidify your basic understanding you will want to ask very specific questions as your question is wildly subjective and to most programmers not really worth answering. Make sure you use correct terminology, stick to core languages and not libraries as doing so will help ensure your working code will last that much longer. The stricter your coding practices the better off you'll be. Maximize the sensitivity of your error reporting for HTTP, JavaScript, PHP and SQL errors. Getting PHP is not set errors? What if a hacker is trying to pry error messages from your code? Make sure those variables are set before you even begin to start working with them. Log your errors and fix them fanatically. Don't try to add every feature in the world, concentrate on the critical functionality first and make sure it's incontestably solid before you expand upon it. Do these things and while it may take more time up front you will be rocking harder than the vast majority of people drowning in live environments that are built on not solid code.
gizmovation is right, you don't need AJAX, but to answer the question "how can I implement PHP in my javascript to..."
You're looking to use AJAX. Use jQuery's .ajax to call the PHP page, and when it returns the result, put it into the javascript variables, or directly into the DOM. AJAX example or jQuery example
I recently created a website where a user logs in and accesses various forms and other things. I was wondering, after login, how can I change the php code so that it automatically modifies a portion of the page making it personal? Here is a screen shot of the front end.
I would like the login form portion disappear and then have a new layout replace it. Would I use Javascript or AJAX. If either, does anyone have any guidance on how to go about doing this project?
It sounds like one of your goals is to minimize page refreshes, possibly having none at all.
Your main challenges include:
1. Managing possibly lots of unrelated DIVs, which make up your functional segments.
2. Speed issues - lots of code crammed into one page.
3. All input sent asynchronously (things get complicated very fast when you want to do EVERYTHING with AJAX!)
As far as your initial login menu, you can fade that out by wrapping it in a DIV and calling jQuery's fadeOut() function on it. To update PHP components without refresh, that's where your AJAX comes in. You're going to want to use a little of each and like therealsix said, they're all essentially Javascipt at the core.
My best advice would be to spend a big chunk of your time dedicated to this project in the planning stage. Understand how you are going to deal with DIVs crashing into each other. Develop an overall table layout that gives you flexibility concerning where content DIVs come in and out. Think about which ones are replaceable at any given time. Study up on modular coding.
That's broad advice because I don't know what exactly the project entails, so if you have any specific issues, let me know.
I would say neither. If you're going to change the whole page, just redirect to a new page.
If you needed to do this without a page reload you would need to use javascript and AJAX (ajax in some sense is javascript). Then I would recommend you look at the jquery functions (http://api.jquery.com/load/)
When I first started web development with php, when using POST I would have the page with the form that contained the information and then another php page which the “action” attribute pointed to and hence where the all the processing i.e. database work was done. After making a website with many forms I found that I was building up lots of pages and it was getting quite messy.
Then I started to look for a way to avoid this. I then found that I could post a page to itself and hence halving the amount of pages that I needed to use to submit a form. I did this using the isset() function in php. The problem with this is that the whole page needed to be refreshed.
Even more towards the future I discovered jquery and its use of ajax to submit forms etc. This led me back to me original problem of having too many pages and getting confused with what did what. So now I am wondering (although I’m not quite sure I can make sense of it) if there is a way to combine the two? Can jquery use ajax to process a form which points to itself?
The other options that I was thinking of would be to have one page that I send all forms and actions to, which has all my processing in and determine which section to use based on a switch. I’m not sure of the effects that this would have on performance though.
What views do you have on each of the methods?
What are the pros/cons?
Are any of the methods I mentioned frowned upon/bad practice?
This question has been baffling me for a while now, and so I thought it best to get the thoughts of the experts.
Thanks in advance.
Adam Holmes.
Well the answer is quite simple. Jquery uses AJAX to request pages the same way as you would with a regular form. Thus you can use jquery to post information from the form on the page itself, and then as you would normally with isset() do whatever you want.
The obvious advantage is that you don't need to refresh the page, and everything seems more seamless. However sometimes you will need to refresh anyway, for instance during logging in. The disadvantage is that users with javascript off will not be able to use that form, however from my experience this now mostly applies on mobile devices, and in limited manner even then.
I would say that using jquery/ajax to submit your forms is the way to go, just be sure to provide javascript-less alternative if it is something essential and if you receive a lot of traffic from mobile devices.
Somebody else will probably provide more elaborate answer, so take this just as a little summary.
jQuery can process it, and send anywhere you want :-)
Don't you thinked about using some kind of classes and autoload ( PHP 5 ) ? - it makes choosing in your second option much simpler ( somepage.php?class=Foo&.... )
I am quite new to web development and have a task to develop a web application that will basically show the user 5-15 pull down lists on one page, where each selection will limit the choices in all other lists. The user should be able to start with any one of the lists (so no set selection order) and when the user have selected something in each list or all parameters are otherwise locked by previous choices the user has to press the GO button and some calculations will take place, presenting a database selection. Basically it is a muliple parameter product selector application.
The relations between the lists are not simple, and could need calculated fields etc, and one list could affect the content of several others. The database behind will be MYSQL, probably a single large table, with perhaps 30 fields and 500-5000 rows. I will be using PHP, JavaScript and perhaps AJAX unless you have a strong reason not to.
I have done some research and found three ways to do this:
Send all data to the browser and handle the filtering etc client side with Javascript.
Send parameters back to the server after each selection and reload the whole form after each selection. Probably a littebit Javascript and most code in PHP.
Use AJAX to change all list content dynamically without reloading the whole form.
Since I am so new to this I have a hard time telling which way to go, what pitfalls there are etc...
I have some conserns:
A. Slow initial loading. Worst for #1?
B. Slow dynamic response. Worst for #2?
C. Complicated programming. Worst for #3?
D. Compatibility issues for different browsers and plattforms. Have no idea of which method is most likely to create problems...better if I use some Framework?
E. Could I even try to make something at least part-working for people with javascript turned off? (like selecting each list on a new page and having to press GO button each time)? (I think I can tell my users they must have Javascript on so no big issue....) Perhaps #2 is best here?
F. I think the specification of "free selection order" means I have to download most of the database initially, so perhaps I should try to avoid that option.....if I keep it I might as well use method #1, or???
G. It would be best to do as much as possible of the selction/filtering in SQL to allow future extensions by building custom SQL code, so that gives a big minus to #1...
H. Other pitfalls etc???
I have found tutorials etc for all three methods, but if you can point to good resources like this I would appreciate it, especially so I dont base my code on examples that are not smart/good/compatible....
1:
http://www.bobbyvandersluis.com/articles/unobtrusivedynamicselect.php
http://javascript.about.com/library/bl3drop.htm
http://www.experts-exchange.com/Programming/Languages/Scripting/JavaScript/Q_20523133.html
2:
http://www.plus2net.com/php_tutorial/php_drop_down_list.php
http://www.plus2net.com/php_tutorial/php_drop_down_list3.php
3:
http://techinitiatives.blogspot.com/2007/01/dynamic-dropdown-list-using-ajax_29.html
http://www.webmonkey.com/tutorial/Build_an_Ajax_Dropdown_Menu
http://www.noboxmedia.com/massive-ajax-countryarea-drop-down-list/
http://freeajaxscripts.net/tutorials/Tutorials/ajax/view/Create_AJAX_Dynamic_Drop_Down_List_using_PHP_-_xajax.html
3+jQuery:
http://remysharp.com/2007/01/20/auto-populating-select-boxes-using-jquery-ajax/
Now to the question: Could anyone experienced in all these methods help me out a bit, with the evaluation of methods 1-3 above so I can choose one and get started on the right track? Also, will I be helped by learning/unsing a framework like jQuery+jSON for this?
Rgds
PM
I'd definitely recommend using AJAX with jQuery its tested in all of the major browsers and has simple calls that will make it a lot faster to code and you wouldn't have the browsers compatibility problems of normal JavaScript.
Send all data to the browser and handle the filtering etc client side
with Javascript.
You mentioned that your table has 30 columns and 500-5000 rows potentially? In that case it would not be a good idea to send that much data when the page loads as: 1. It will make the page slower to load and 2. It is likely to make the browser hang (think IE).
Send parameters back to the server after each selection and reload the
whole form after each selection.
Probably a littebit Javascript and
most code in PHP.
I'm not sure how this differs much from the third approach, but probably you mean that you need to reload the page? In that case it isn't likely to be a good user experience if they need wait for the page to refresh every time a drop down selection is changed..
Use AJAX to change all list content
dynamically without reloading the
whole form.
By far the best approach from a user's perspective as it makes filling out the form simple. Perhaps slightly harder to implement from your end, but as you would likely need to perform the same calculations with each of the solutions - might as well move them to a separate page that can be called by AJAX to retrieve your data. As others have mentioned, using jQuery for all your JavaScript/AJAX stuff is going to make things a hell of a lot easier ;)
My personal recommendation is to go with AJAX.
Raw SQL or not is really a question of what backend you are using.
You need to be able to set the relationships between the different selections. The population of the lists must be able to communicate with your backend.
The real issue here is how you implement the relationships between selections. I have no good answer here, it depends heavily on the backend and your administrative needs. It can be hard coded in PHP or configured via XML or via administrative interfaces and persisted to your database solution.
It's no easy task to make it fully customizable.
The reason why i suggest using AJAX is basically because you need to filter upon any change in any selection. That would mean either download a lot of unused information or a lot of page refresh. Going with ajax gives the user a smooth experience all the way.
jquery is a simpple way to use... You can also try a particular class called xajax..! These will make stuff easier.
When is it appropriate to use AJAX?
what are the pros and cons of using AJAX?
In response to my last question: some people seemed very adamant that I should only use AJAX if the situation was appropriate:
Should I add AJAX logic to my PHP classes/scripts?
In response to Chad Birch's answer:
Yes, I'm referring to when developing a "standard" site that would employ AJAX for its benefits, and wouldn't be crippled by its application. Using AJAX in a way that would kill search rankings would not be acceptable. So if "keeping the site intact" requires more work, than that would be a "con".
It's a pretty large subject, but you should be using AJAX to enhance the user experience, without making the site totally dependent on it. Remember that search engines and some other visitors won't be able to execute the AJAX, so if you rely on it to load your content, that will not work in your favor.
For example, you might think that it would be nice to have users visit your blog, and then have the page dynamically load the newest article(s) with AJAX once they're already there. However, when Google tries to index your blog, it's just going to get the blank site.
A good search term to find resources related to this subject is "progressive enhancement". There's plenty of good stuff out there, spend some time following the links around. Here's one to start you off:
http://www.alistapart.com/articles/progressiveenhancementwithjavascript/
When you are only updating part of a page or perhaps performing an action that doesn't update the page at all AJAX can be a very good tool. It's much more lightweight than an entire page refresh for something like this. Conversely, if your entire page reloads or you change to a different view, you really should just link (or post) to the new page rather than download it via AJAX and replace the entire contents.
One downside to using AJAX is that it requires javascript to be working OR you to construct your view in such a way that the UI still works without it. This is more complicated than doing it just via normal links/posts.
AJAX is usually used to perform an HTTP request while the page is already loaded (without loading another page).
The most common use is to update part of the view. Note that this does not include refreshing the whole view since you could just navigate to a new page.
Another common use is to submit forms. In all cases, but especially for forms, it is important to have good ways of handling browsers that do not have javascript or where it is disabled.
I think the advantage of using ajax technologies isn't only for creating better user-experiences, the ability to make server calls for only specific data is a huge performance benefit.
Imagine having a huge bandwidth eater site (like stackoverflow), most of the navigation done by users is done through page reloads, and data that is continuously sent over HTTP.
Of course caching and other techniques help this bandwidth over-head problem, but personally I think that sending huge chunks of HTML everytime is really a waste.
Cons are SEO (which doesn't work with highly based ajax sites) and people that have JavaScript disabled.
When your application (or your users) demand a richer user experience than a traditional webpage is able to provide.
Ajax gives you two big things:
Responsiveness - you can update only parts of a web page at a time if need be (saving the time to re-load a page). It also makes it easier to page data that is presented in a table for instance.
User Experience - This goes along with responsiveness. With AJAX you can add animations, cooler popups and special effects to give your web pages a newer, cleaner and cooler look and feel. If no one thinks this is important then look to the iPhone. User Experience draws people into an application and make them want to use it, one of the key steps in ensuring an application's success.
For a good case study, look at this site. AJAX effects like animating your new Answer when posted, popups to tell you you can't do certain things and hints that new answers have been posted since you started your own answer are all part of drawing people into this site and making it successful.
Javascript should always just be an addition to the functionality of your website. You should be able to use and navigate the site without any Javascript involved. You can use Javascript as an addition to existing functionality, for example to avoid full-page reloads. This is an important factor for accessibility. Javascript should never be used as the only possibility to reach or complete a request on your site.
As AJAX makes use of Javascript, the same applies here.
Ajax is primarily used when you want to reload part of a page without reposting all the information to the server.
Cons:
More complicated than doing a normal post (working with different browsers, writing server side code to hadle partial postbacks)
Introduces potential security vulnerabilities (
You are introducing additional code that interacts with the server. This can be a problem on both the client and server.
On the client, you need ways of sending and receiving responses. It's another way of interacting with the browser which means there is another point of entry that has to be guarded. Executing arbritary code, posting data to a non-intended source etc. There are several exploits for Ajax apps that have been plugged over time, but there will always be more.
)
Pros:
It looks flashier to end users
Allows a lot of information to be displayed on the page without having to load all at the same time
Page is more interactive.