How can you dynamically load Javascript functions using Ajax?
(Rhetorical Question)
I ran into a bizarre scenario today where I wanted PHP to update how the javascript behaved on-the-fly. It was irritating, here is what I tried...
/*
* ajax-php-javascript-function-loader.php
*
* this gets called by AJAX and defines or re-defines the
* definition of dynamicDoStuff()
*/
<script type="text/javascript">
function dynamicDoStuff(a,b){
<?php
//dynamically defined function behavior
?>
}
</script>
This did not work because when the new javascript was loaded, it's scope of the new function definition was limited to the new script tag开发者_C百科s. Scripts elsewhere on the page couldn't read it.
So here is what you have to do.
/*
* index.html
*/
<html>
<head>
<script type="text/javascript">
var dynamicDoStuff;
</script>
<!-- Other Head Stuff -->
</head>
<body>
<!-- the body of the site -->
</body>
</html>
and
/*
* axax-php-javascript-function-loader.php
*/
<script type="text/javascript">
dynamicDoStuff = function(a,b){
<?php
//dynamically define function behavior
?>
}
</script>
by defining the name of the function in the header it becomes globally accessible so you can re-purpose it dynamically using ajax and (php or whatever)
Instead of just
function newFunctionViaAjax() { ... }
you could instead use
window['newFunctionViaAjax'] = function newFunctionViaAjax() { ... };
A better approach may be to just have your AJAX method return data, in this case, a flag indicating which behavior your the method in question should adopt.
var ajaxResponseHandler = function(jsonResponse) {
dynamicDoStuff = jsonResponse.someFlagFromTheServer == someExpectedValue
? staticDoStuffA
: staticDoStuffB;
};
Ideally, at least in most situations, your AJAX method should just return data anyway.
Also, with this method, you can have the required alternate behavior defined in a normal JavaScript file that is already loaded by the client, instead of mixing JavaScript in with your PHP.
加载中,请稍侯......
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