I have this script in index.php file:
<script type="text/javascript">
$(document).ready(function(){
$('#ads').load('output.php').fadeIn('slow');
});
</script>
And the output.php file contains a hidden input by which I pass a php variable and retrieve it succesfully:
<script type="text/javascript">
num = document.getElementById('number').value;
</script>
And if I put, say, an alert(num); in the output.php file, everything works. Though when I do the same in the index.php file, javascript doesn't seem to see that num variable.
Im just going to ges that you dont actually wait until the file is actually loaded before testing to access that variable
http://api.jquery.com/load/
the load method takes a completed callback that u can use like this
$(document).ready(function(){
$('#ads').load('output.php', function() {
alert(num);
}).fadeIn('slow');
});
but you should probably not solve your problem this way i sugest you call a function from your
loaded file instead of setting a variable
You can't access variables before you create them. In the code you provided the first time num is being assigned to is when the output.php file is loaded and parsed. Since jQuery's load function isn't blocking - that is, your browser will continue executing JS while the load function is doing its magic - you have no good way to know when num will be assigned to. It could be milliseconds, or it could be never if your webserver refuses to return the output of output.php for whatever reason.
In jQuery programming, using a callback function is common practice, although you can make it cleaner by passing it a function reference instead of an inline function:
$(document).ready(function(){
$('#ads').load('output.php', outputLoadCallback).fadeIn('slow');
});
function outputLoadCallback(response, status) {
console.log(num);
}
Maybe an even better way would be to include the logic you need to run in the callback function like so:
var num; // Make sure num is in the global scope
function outputLoadCallback(response, status) {
num = document.getElementById('number').value;
console.log(num);
}
If you're "not much of a pro", may I suggest jQuery in Action?
Related
I am building a chat. I have this Jquery working code which calls logs.php every second and refreshes the chat.
$(document).ready(
function(e) {
$.ajaxSetup({cache:false});
setInterval(function() {
$('#chatlogs').load('logs.php');
updateScroll();
}, 1000);
}
);
As you can see, also updateScroll, a JS function on my page, gets called. Updatescroll creates a variable, which I would like to pass on to logs.php, is there any way to do this? In other words, updatescroll basically checks everysecond if the user has scrolled up to the top of the chat. If so, I am gonna tell logs.php to load -say - another 10 messages. But in order to do this, I have to have something that from updatescroll passes on to the Jquery function and thus onto logs.php. You get it? Thanks
First, when it comes to ajax, I would recommend using a window.setTimeout, intervals can get tricky when you are running things asynchronously (if one call hangs you can end up with multiple calls to the same script).
so something more like:
(function($){
var update_messages = function(){
var count = updateScroll();
$('#chatlogs').load('logs.php?count='+count, function(){
window.setTimeout(update_messages, 1000);
});
}
$(document).ready(function(){
$.ajaxSetup({cache:false});
update_messages();
});
})(jQuery);
Then in your PHP script the "count" would be available via $_GET['count'].
EDIT: you can see an anonymous function is being sent as a second argument to load, this will be called AFTER the AJAX call is complete, so we can make sure only 1 of these is running at a time
I have a javascript code that I wanna put a php on it.Then in middle of php code , put a javascript variable.
like this :
<script>
function getuserid(id,shop){
...
var htmlString="<?php $_SESSION['SELECTED_CID']= {I want to put 'id' variable here}?>";
}
</script>
PHP code was compiled and run once when you done loading your page. But javascript function can be used many time! So, some function like this does not exist.
You can use Ajax to accomplish what you want, whenever you wanna retrieve UserID, you can call an ajax, then ajax do a request to server and return you what you need!
Have a try :)
I have the following in the body of a php page:
<?php if($foo) : ?>
<script>
js_func();
</script>
<?php else: ?>
//Do Something else
<?php endif; ?>
Based on the PHP conditional I either do or do not want to run js_func().
However if I am loading all of my scripts (including the script the defines js_func()) at the bottom of my page this will results in an error.
One possible solution would be to load the external script BEFORE calling js_func() but I understand that for performance reasons I shouldn't do that.
I could use $(document).ready(function() {}); but this just moves the error as jQuery is also loaded in the footer.
The only other options I can think of is to use window.onload or never call a js function inline. How does everyone else solve this issue?
Many thanks.
EDIT:
#Nile - Im not sure what you mean. Why would I comment out code that I want to execute?
#haynar1658 - I don't want to execute JS in the else scenario.
#Matthew Blancarte - Understood. That leads to my question, what's the best way to make sure that the js I need loads before that function is instantiated? Include the script before it? Use window.onload? etc.
I think you are making a rod for your own back. Depend on the question you described, you want to put all the function definition script block after the place where them being called. It's Impossible!
If you indeed need to do this, does this can help? :
<script>
var fns = []; /* use fns to keep all the js code
which call the functions defined after. */
</script>
<script>
//wrapp your code in a function and then push it into fns.
fns.push(function(){
js_func();
})
</script>
//script tags for loading your function definition js script.
<script src="path/to/jquery-any-version.js"></script>
<script src="path/to/other-libraries.js"></script>
<script>
//after your definition js scripts are loaded , call all functions in fns
for(var i=0, len=fns.length; i<len; i++){
var fn = fns[i];
fn.apply(this, []/* arguments that provided as an array */);
}
</script>
Just move the script to the top.
The difference (if there is one) is very small.
The believe that putting the <script>s in the <head> slows down the page is not "accepted" by all developers.
Did you try to echo it in PHP?
<?php if($foo) {
echo "<script> js_func(); </script>";
}else{
echo "something else";
}
Consider the following code:
<script src="js/backgroundChanger.js" type="text/javascript"></script>
<script>
$(document).ready(function() {
$('.Themes').click(function(){
$('#dcontent').load('printThumbs.php');
});
});
</script>
The first script is for background changing logic and the second script gives list of thumbnails of the themes. The problem is that the first script doesn't work beacause of the second. If I don't use this AJAX technique everything works fine. Working code:
<script src="js/backgroundChanger.js" type="text/javascript"></script>
<div id="dcontent">
<?php include('printThumbs.php'); printThemesThumbs();?>
</div>
The background changing logic looks like:
$(function() {
$('.themes li a img').click(function() {//code
});
Any help will be greatly appreciated.
in your first snippet of the code you defined a click function on .Theme and in the third snippet of the code .theme, is this correct?, i mean both classes seems to be different try to use the same class name return by your php function.
You're calling $(document).ready() twice, as $() is an alias, and the second definition is overwriting the first. First you are setting the document ready callback to
function() {
$('.themes li a img').click(function() {//code
}
and then overwriting it with
function() {
$('.Themes').click(function(){
$('#dcontent').load('printThumbs.php');
});
}
you have to add your second code in a callback function. you can't bind something if it is not already in the dom. if you want to make changes to the printThumbs output you need to add a callback...
<script>
$(document).ready(function() {//this is also a callback function when document is ready
$('.Themes').click(function(){//this can be understand as a call back too... code is fired after a click
$('#dcontent').load('printThumbs.php',function(){/*your callback code here...this code will be fired after you've loaded printThumbs*/}
});
});
</script>
if you want to do some jquery or other client side stuff on the respons of an ajax call (html,xml, json or whatever) you have to specify a callback function. to make things less complicated you have to look at the callback function just as the on document ready function with the difference that the callback is applied to the respons of your ajax call. if the code is not in a callback function you can't manipulate the respons because it is not injected in the dom/it simply does not exists in your browser when the document is ready.
basically I am trying to call a javascript function from my PHP and I am using code I know works in other situations however here is it not and I am at a loss as to why?
It may be something stupid as I have been staring at this screen for a long time :)
here is where I call the function:
if(isset($test_details['done_test'])){
echo "getting here";
echo "<SCRIPT LANGUAGE='javascript'>user_error();</SCRIPT>";
}
I successfully get 'getting here' printed however it does not call the JS function.
javascript function:
function user_error(){
document.write("working");
//alert("User has already taken this test. Your are being redirected...");
//setTimeout("window.location='home_student.php'",3000);
}
The commented it what I do eventually want it to do.
Could anyone please shed some light.
Many thanks,
#Crimson - Here is what I tried after your advice...still no luck.
javascript now:
$(document).ready(function () {
var done = "<?= $test_details['done_test'] ?>";
if(typeof done != 'undefined'){
$('WORKING').appendTo('#bodyArea'); // just to test
}
});
By echoing <script>...</script> with PHP, you are not going to get the browser run the JS function!
PHP only outputs the HTML file that you want to send to the browser. The browser then parses this HTML and does a multitude of things before the page is displayed to the user.
Next, the user interacts with the displayed page (or some other browser related event like 'onload' happens) and the attached JS gets called.
So, if there is some JS that you want to run at a certain time, say immediately after the browser has finished loading the page, you need to create JS in the HTML file such that there is a JS function which gets called at the page load event like this:
<body onload="/*do something here*/"> ... </body>
It is better to use JQuery or some other JS frmework to accomplish something like this though.
Are you sure the function is already defined? Perhaps you declared your function after making the function call.
Additionally, although it's not really going to matter here, the proper way to have a javascript script tag is.
<script type="text/javascript"></script>
i.e. not language="javascript"
Replace the line you call the JS function with this:
echo '<script type="text/javascript">window.onload = user_error </script>' ;
It should solve the problem. Because at the time you are calling user_error(), the function may not have been initialized by the browser. So you'll get an error since the function could not be found.
If the function is placed in an external .js file, it's very likely that you get this error, since the external file usually takes a while to be loaded. If the function deceleration is in the same file but after where you are calling it, same thing happens.