I have page that has some javascript that needs to run at page load. Said javascript needs to locate the client-side component of a ServerControl, which it does with $find().
Of course, if I emit my code directly onto the page, it executes as the page is being read, and fails because nothing it depends on is yet initialized.
If I put my code inside a pageLoad() function, it runs just fine, because asp.net automatically wires up an onload handler for any function named pageLoad(). The problem is I really don't like the pageLoad() solution - mainly because it's a single global name. If I commit some code using pageLoad(), I just know that some other programmer is going to copy the approach, somewhere inappropriate, and we're going to end up with a page that includes two or more different pageLoad() functions, and the result will be a bunch of mysterious errors that will take forever to track down.
So, I put my code inside an anonymous function passed to jquery's $(document).ready(). This fails, because it runs before the ServerControl's client-side component exists.
So, I put my code inside an anonymous function passed to by Sys.Application.add_load(). This also fails, because Sys is undefined.
So I finally settle on putting my code inside Sys.Application.add_load(), and then put that inside a function called by $(document).ready(). This works, but it gives nearly as much heartburn as pageLoad().
<script type="text/javascript">
$(document).ready(function(){
Sys.Application.add_load(function(){
var component = $find(<clientid>);
if (component) { <do something> }
});
});
</script>
There has to be a better way of handling this.
Any ideas?
If you have control over the code-behind, you can register the JavaScript to run at startup via something like:
this.Page.ClientScript.RegisterStartupScript(
this.GetType(),
"StartupScript",
"Sys.Application.add_load(function() { functioncall(); });",
true);
As long as your component has been loaded via Sys.Application.add_init() you should be fine...