Another question by a newbie. I have a php variable that queries the database for a value. It is stored in the variable $publish and its value will change (in the database) when a user clicks on a hyperlink.
if ($publish == '') {
Link to publish.html
} else {
Link to edit.html
}
What is happening in the background is i am querying a database table for some data that i stored in the $publish variable. If the $publish is empty, it will add a link for publish.html in a popup. The popup will process a form and will add the data to the database and which means that the $publish is no more empty. What i would like to achieve is that as soon as the form is processed in the popup and a data has been added to the database, the link should change to edit.html. This can happen when the page will re-query the database but it should happen without page refresh.
How can it be donw using javascript, jquery or ajax?? Please assist.
Javascript by itself cannot be used to deal with database. That is done using php (Or the server side language of your choice). Ajax is used to send a request to your php script using javascript which will in turn communicate with the db. And it doesn't require a page refresh.
So what you are trying to do can be easily achieved using ajax. Since you mentioned jquery, you can check out the $.ajax or $.post methods in jquery which make the process even more simple.
You need to process the form using ajax. The ajax request is sent to a php script which will make the necessary changes in the database and send the new link (link to edit.html) in the response. Upon getting the response, just replace the current anchor element with the new one ..
for eg..
$.post(url, formdataobject , function (resp) {
$("a.youra").text('edit').attr('href', resp);
});
url - where the php script is located
formdataobject - a javascript object that will have the form data as key value pairs
the third parameter is an anonymous function also known as callback function since it will be invoked only when the response is received from the server. This is because ajax requests are asynchronous.
Inside the callback function, jquery is used to change the text inside the anchor element to edit and the href attribute is changed to value that came in the response.
$.post means we are using the post method. so the parameters can be accessed as elements of $_POST array in php.
After updating the db, you can simply echo out the new link and it will be received in the response.
Also, there are other formats in which you can get the response for eg. xml, json.
I'll try to leave the technical jargon aside and give a more generic response since I think you might be confused with client-side and server-side scripting.
Think of javascript as a language that can only instruct your WEB BROWSER how to act. Javascript executes after the server has already finished processing your web page.
PHP on the other hand runs on your web server and has the ability to communicate with your database. If you want to get information from your database using javascript, you'll need to have javascript ask PHP to query the database through an AJAX call to a PHP script.
For example, you could have javascript call a script like:
http://www.myserver.com/ajax_function.php?do=queryTheDatabase
In summary: Javascript can't connect to the database but it can ask PHP to do so. I hope that helps.
Let me try, you want to change the link in a page from a pop-up that handles a form processing. Try to give your link a container:
<div id="publish_link">Publish</div>
As for the form submission use Ajax to submit data to the server to do an update and get a response back to change the link to edit or something:
$.post("submit.php", { some_field: "some_value"}, function(response) {
if(response.isPublished)
$('#publish_link', window.opener.document).html('Edit');
});
Basically your publish link is contained in a div with an ID publish_link so you change its content later after data processing without reloading the page. In the pop-up where you would do the form processing it is done using jQuery Ajax POST method to submit the data. Your script then accepts that data, update the database and if successful returns a response. jQuery POST function receives that response and there's a check there if isPublished is true, get the pop-up's opener window (your main window) and update the link to Edit. Just an idea, may not be the best out there.
It cannot be made with javascript, jquery or ajax. only server side script can query a database. with ajax request you can get the script output. ajax requests can be sent either with pure javascript or jquery.
Well, i think i understand your quaestion, but you have to get a starting point, try to understand this:
try to understand what are client variables and server variables.
javascript does not comunicate with database.
you can use javascript to retrieve data to a specific "Object variable".
Using ajax methods of jquery you can post that data do other page, that will execute the
proper actions
you can ;)
at first you must create php file to query database and return something like true or flase and then with file url check the function and get answer
function find_published(folder_id) {
var aj_url = "{{server_path}}/ajax/url"
var list;
$.getJSON(aj_url+"?callback=?&",
function(data) {
//here is your data... true false ... do every thing you want
}
);
};
this app for node.js does mysql queries https://github.com/felixge/node-mysql
You need to use AJAX for this, like .post() or .get() or JSON.
Related
I am working on a project where I used ajax for asynchronous DB access.
I store the value in JavaScript variable as follows..
var content=xmlhttp.responseText;
now what I wanted is to pass this value to the php module on same page..
Please suggest me..its urgent
You'll have to make a separate AJAX request to another script to achieve this. PHP is server-sided and therefore cannot directly interact with the client.
You should handle the data (which you are assigning to content) in PHP because, as the other answers here tell you, PHP is server-side and JavaScript is on the client. If you are getting this data from a page you control, instead of var content = xhr.responseText; just modify the data BEFORE you send it. For example, if you are making an AJAX call to a process.php file on your server to get the data you are otherwise assigning to content in JavaScript, be sure to handle the data in process.php PRIOR to echo()'ing the data (which you are then storing inside content on the client):
In process.php:
// below is the normal server script which you are storing in content on the client
// echo $result;
// instead, we are going to operate on the data first:
return doSomething($result);
Then on the client:
var newContent = xhr.responseText;
And the newContent variable will contain the data you previously wished to modify with PHP. If you DO NOT have control of the server script which you are calling with AJAX, then as mentioned here already, you will need to send a SECOND AJAX call to the server with your PHP, and use $_GET or $_POST to retrieve that content data and then play with it there.
Am unclear about your need to pass value from javascript to php.
But I can give you,
A non-recommended but working approach towards your problem:
You said, you are making an Ajax call at first. While processing the corresponding server side php function, Store the response value (value of xmlhttp.responseText) into a $_SESSION variable. Finally Reload the page (using location.reload()) inside the ajax response handler function.
And a recommended approach towards your problem:
You might have added some if-else control-flow structures in the php code and expecting to execute them after getting the ajax response value (sadly you cannot do that). So if you do have some logic like that, then convert those if-else conditions to corresponding Javascript code. May be a javascript function and call that function by passing the ajax response value to it. This new function will use your ajax response value and make changes in some parts of your webpage by applying necessary logic.
I am very new to this javascipt, jquery world and I am having great difficulty getting to grips with it.
I have got the following in my HTML
$(document).ready(function(){
$("#frmEnquiry").validate();
});
</script>
It works although I do not understand, what is going on behind that statement, especially as it validates on each field entry (which is wonderful).
I have action="" in my form definition and a submit button and I have created a process.php file which further validates and sends an email, but I have no idea how I call that php file or where I put the call or what the syntax is for doing it. I am assuming it is based on a return from validate().
Also what is the correct procedure for returning from the PHP file with either success or failure messages.
If anyone can help at a simple syntax level, I would be most grateful as I have looked at so many possible solutions, my head is just totally confused.
I apologise for probably asking a very common question, but when you are just starting, it is difficult finding an example which you fully understand.
Well, there are two general approaches:
Oldschool form processing: you set <form action='process.php'> so your request is submitted to that page. Browser reloads and displays the content that you have rendered in process.php
Ajax-submit: this way you leave action blank, block submitting with something like <form onSubmit = 'return false'> and then send content using one of jQuery's AJAX-methods: get, post or ajax. It looks something like that:
$(document).ready(function(){
if($('form').validate()){
$('form').submit(function{
//Personally I prefer ajax as get and post are just shorthands for this method
$.ajax({
url:'process.php',
dataType:'json',
data:{name:nameVal, value:valueVal}
success: function(){
/*server returned some data, process it as you wish*/
}
});
});
}
});
Don't forget the principles:
PHP is executed server-side
javascript is executed client-side
Thus, PHP will only be executed if you are calling the server, meaningly, if you call an URL (http://mydomain.com/MyPHPpage.php) or if you are calling your server through an AJAX request (which is seemingly the same, except there is no reload client-side).
On the contrary, javascript is called only client-side. So the code used to validate() your form is called only on the client-side (except if you have a specific function behind this that would call the server). Hence, the javascript will use the parameters you gave him to validate the form without calling the server. This is a very good way not to overload your server with un-wanted request (empty fields, wrong e-mail addresses...).
Anyway, you can still have some other checks on your server side (checking in your database if the user exists...) and return another message to the user.
To answer your question, i'll ask some other ones: what are you trying to validate? do you want to check client-side or server-side? which data and for which purpose?
You need an AJAX call to your PHP script. If your form data is valid you would do such a call. You can asign a success callback to the ajax request where you can process the return data from PHP and either update data, display a error message or something else. From PHP you can return an object or an array where you detail if errors occured and of what type. More about AJAX -> http://api.jquery.com/jQuery.ajax/
In your case it is reasonable to perform form validation via javascript by checking the value of each field.
There is no need to send data to the server and receive information about their correctness. This method complicates the validation and is not improve protection against bad data.
Im not sure if this is possible, but at the moment I have a form on my page where users can insert their interests, beneath that form are 3 PHP variables (Which dont currently show at first as there is no value assigned to them).
When a user enters an interest and clicks submit, my AJAX takes over, populates the table and then reloads the page so the Variable now shows as it has a value.
Is it possible to not have to refresh the page, so I can say "if success $var = 'value';"?
I hope this doesnt sound too confusing, thanks
Since you're already using AJAX, why don't you just do the logic using Javascript? If you're using jQuery, have a success callback function execute the code you want.
The problem with sending data from AJAX to PHP is that PHP is a server side language, while AJAX is a client side one. By the time your browser sees the page, the PHP has been entirely executed and returned to you as HTML / CSS / Javascript etc.
No, you can't. By the time the HTML has rendered/displayed in the browser, PHP will most likely have long since finished generating the HTML in the first place. You could round-trip the values through an AJAX handler and then populate the places in your page where the values are displayed, but when why bother round-tripping? Just have the AJAX call fill in the values right then and there.
It is absolutely possible, and quite easy to do. Just make another php script and call it from your form page's javascript (I'm going to assume you're using jQuery):
$('#mysubmit').click(function() {
$.getJSON(
'form_ajax.php', // This is the php file that will be called
{ formVar1: $('#form-var-1').val() }, // Add all your form data here
function(data) {
// This is the function that is called after the php script is
// done executing. The 'data' variable will contain the $data
// array you see in the following php file.
}
);
});
I prefer to use JSON, but other approaches are just as good. Check out the documentation for getJSON() and ajax(). Your php file would look something like this:
<?php
$data = array();
if ($_SERVER['REQUEST_METHOD'] == "POST") {
$data['formVar1'] = $_POST['formVar1'];
}
echo json_encode($data);
?>
Of course, yours would probably do a lot more with the form data. Also, theres plenty of other approaches so go explore for the one the best suits your needs.
Ok so trying to get a page together that needs to connect to our SQL database. So on the javascript page I have functions that will autocomplete a textbox with data out of our mysql DB and then I need to send it to other functions and classes so that it will then look in our SQL DB and return some data. The problem I have is trying to get the .GET call to call in the php page, with the function that calls the class in which I need to get into for the SQL call. I have it setup somewhat but trying to figure out how to send the data through with it as well as just get clarification on how to work the .GET function.
Javascript page:
$.get("dsl_validate.php", calldsl(job));
Php Page
function calldsl($job){
var $dsljob = $job
hasfunctioncode($dsljob);
}
The hasfunctioncode function is in my DSL class page that will return the info I need. Any help on if I am in the right direction or not?
It looks like you're trying to physically call the PHP function calldsl() from the JavaScript. This... isn't right. (I'm assuming the $.get() you're using is from jQuery, please correct me if that assumption is incorrect.)
What $.get() does is simply call a resource on the web server. It doesn't have any knowledge of the server-side code (nor should it, for a number of reasons). From the perspective of the server-side code, there's no difference between a page being called via $.get() vs. one that's just loaded in a web browser.
What you essentially need to do is create a PHP page which accepts arguments either as a form post or query string (if you're using $.get() then the query string is the way to go), does its server-side logic, and then simply outputs the results to the "page." In the case of calling the page via AJAX as you are here, it's a good idea to render the page content using JSON notation. (Don't forget to set the content-type header to "application/json" as well.)
Then what you're getting on the client-side from the $.get() call is the response body, which would be that JSON data. It's really just a "page" like any other, the only difference is the content-type telling the browser that it's JSON data and that it doesn't have HTML, just JavaScript objects. The success callback on the $.get() call (the function you pass it, or create in-line) would receive that response data as an argument and can do what you need to with it.
The way I understand jQuery.get(), the second argument is the "callback" (http://api.jquery.com/jQuery.get/). The callback will hand the results from your server therefore should be a function. Currently your code actually executes the function "calldsl" where you should be only passing a reference like so...
Javascript:
$.get("dsl_validate.php", function(response){
alert("yay I haz ajax! "+response)
});
PHP: "dsl_validate.php"
echo "this is some data from the server";
No, your are not in the right direction. The first parameter of the get method have to br the complete URL of the page, not just the script (this works if the script resides on the same directory of the javascript file, though). The .php file shall return somehting "usable" for you javascript (JSON, or HTML, or text, or... whatever). The "calldsl" function will be called AFTER the data has been returned from the call. Something like that:
$.get('dsl_validate.php?value=somevalue', function(data) {
alert("Data returned from dsl_Validate: " + data)
});
i think you are better off passing the function as a param to your php page
$.get("dsl_validate.php?calldsl="+job, function(data) {
$response = $(data);// create a jquery object from the response
});
`
and in your php file
create a switch statement that call the function based on the parameter
Mmm I think you are wrong, the second argument on your get function is the javascript function that will process de data returned by "dsl_validate.php". I mean, if that page returns "foo", job will contain "foo".
But in my experience is better to use the autocomplete plugin from Jquery UI
jquery autocomplete plugin
I want to call a PHP function when pressing on a button, sort of like:
<?php
function output(){
// do something
}
?>
<input type="button" value="Enter" onclick="output()"/>
I tried to make something like:
<input type="button" value="Enter" onclick="test.php?execute=1"/>
where test.php is current page and then by php
<? if(isset(&execute)){ echo "Hello"; } ?>
but it doesn't work.
Since PHP runs on the webserver, and buttons (and JavaScript in this case) appear on the client, you have to make an HTTP request to the server.
The easiest way to do this is to use a form. No JavaScript is required. You can add JavaScript (although it should be layered on top of a working non-JS version). Using JavaScript to make an HTTP request without leaving the page is known as Ajax, and generally achieved with the XMLHttpRequest object. There are various libraries such as YUI and jQuery that can do some of the heavy lifting for you.
I think using an AJAX call would do sort of what you are asking. I don't know PHP very well but you can use the following example, and add another variable with the data you are passing in to the server to indicate which function you want to call on the server. On the server you can add some "IF" statements that will call a certain function based on the name passed in and return the result.
Here is what you could use on in your javascript client using the jQuery library as a helper to do the AJAX call:
<input type="button" value="Enter" onclick="output()"/>
<script type="text/javascript">
function output(){
$.ajax({
type: "POST",
url: "submit_data.php",
data: "username=" + "SomeUser"
+ "&email=" + "someEmail#google.com"
+ "&functionName=" + "theFunction1",
success: function(html){
alert('sucess! Result is:' + html);
}
});
}
</script>
and you can use code such as this to catch the data your javascript is passing in. In this example you would want to call this file name as "submit_data.php" to match the javascript above:
<?php
// Variables
$Username = $_POST['username'];
$Email = $_POST['email'];
$FunctionName = $_POST['functionName'];
//Add code here to choose what function to call and echo the result
// If $FunctionName equals 'theFunction1' then execute theFunction1
// If $FunctionName equals 'theFunction2' then execute theFunction2
echo "You called A Page!";
?>
Here I am doing nothing with the "username" and "email" simply grabbing it and storing them into holding variables. But you can easily add extra functionality here, such as checking for a name of a function that you want to run.
PHP is server side and javascript is client side. So I'm not sure if that is really what you want to be doing??
Perhaps you could explain why you want to specifically call a php function?
I googled PHP function from button and found this question on webdeveloper.com
It doesn't use Javascript.
This is PHP you're talking about, not ASP.NET. In PHP, there is no such thing as a button click event. PHP runs entirely on the server and has absolutely no knowledge of client-side events.
Your first try won't work because the PHP code only runs when the page first loads. It does not run when you call a JavaScript function. Your second example won't work because JavaScript and PHP can't talk directly to eachother like that. Trying to directly call a PHP function from JavaScript just doens't make sense. Remember, PHP only runs on the server. By the time you get to the point where JavaScript can run, the PHP code has long since completed its work.
If you want to do something when a button is clicked, you have to explicitly make a request back to the server. You can do this by just POSTing the form as CTphpnwb suggested. Just be aware that this will reload the page and you will have to manually save and restore the page state, e.g. repopulate input boxes. There is no built-in magic that will do this for you.
Alternatively, you can get all AJAXy and do the POST in JavaScript. However, you will have to write the JavaScript to send the request and process the response, and write the server-side PHP code to handle the request. This gets a little awkward to do in a single page.
From : http://www.dreamincode.net/forums/showtopic72353.htm
You cannot directly invoke a PHP function from Javascript this way :
PHP code is executed on the server
HTML / Javascript are interpreted on the client-side.
One the HTML page has been generated and sent to the client (the browser), there is nothing more PHP can do.
One solution would be to use an Ajax request :
Your onclick event would call a Javascript function
This Javascript function would launch an Ajax request : a request sent to the server
The server would then execute some PHP code
And, then, return the result of that execution to the client
And you'd be able to get that result in your Javascript code, and act depending on what was returned by the server.
There are plenty of solutions to do an Ajax request :
You can re-invent the wheel ; not that complex, I should say -- but see the next point
If already using a Javascript framework, like jQuery, Prototype, ... Those provide classes/methods/functions to do Ajax requests
Googling a bit will get you lots of tutorials/examples, about that ;-)