Hook a javascript event to page load

javascript master-pages asp.net onload-event

63,194

Solution 1

If you don't want to explicitly assign window.onload or use a framework, consider:

<script type="text/javascript">
function startClock(){
    //do onload work
}
if(window.addEventListener) {
    window.addEventListener('load',startClock,false); //W3C
} else {
    window.attachEvent('onload',startClock); //IE
}
</script>

http://www.quirksmode.org/js/events_advanced.html

Solution 2

Insert this anywhere in the body of the page:

<script type="text/javascript">
window.onload = function(){
    //do something here
}
</script>

Solution 3

The cleanest way is using a javascript framework like jQuery. In jQuery you could define the on-load function in the following way:

$(function() {
    // ...
});

Or, if you don't like the short $(); style:

$(document).ready(function() {
    // ...
});

Solution 4

window.addEventListener("load", function() {
    startClock();
});

This will invoke the startClock function at page load.

View more solutions

63,194

Jagd

If there was a bronze badge for "Asked a dumb question", I'd have a whole lot of bronze badges.

Updated on July 09, 2022

Comments

Jagd almost 2 years
I have an aspx that has the following javascript function being ran during the onload event of the body.
```
<body onload="startClock();">
```
However, I'm setting the aspx up to use a master page, so the body tag doesn't exist in the aspx anymore. How do I go about registering the startClock function to run when the page is hit and still have it use a masterpage?
Jason Bunting almost 15 years

+1 - I was too lazy to type this answer, but this is the way I would suggest someone does it too, with the same assumptions you initially state.
Jason Bunting almost 15 years

Of course, I would abstract the details a wee bit - hopefully that is obvious to the OP...
Jagd almost 15 years

I must be missing something real obvious here, but where does the 'if' block of code go? You can't just dump that in a <script> tag can you?
Corbin March almost 15 years

You can stick it all in a script tag. I updated my answer to reflect it. This will force the 'if' logic to execute as the script is parsed so the startClock event is ready onload.
Jagd almost 15 years

Easy and slick way to do it. Thanks.
Corbin March almost 15 years

Since non-MS browsers are pretty good about implementing W3C DOM Level 2 recommendations, the 'else' exists for IE only. As Jason mentioned, we could(should) abstract the details and while we're at it we could add caution(is this a browser that doesn't support either event reg. model, is this function already registered, etc). I opted for simplicity in my example. Worth a downvote? I dunno.
Jagd about 14 years

Agreed. I've actually started using jQuery a few months after posting this question (nearly a year ago now), and I love it.
Doug Domeny almost 13 years

Newer versions of jQuery require the $(document).ready(...) style.
ThiefMaster almost 13 years

No. In never versions the behaviour of $() changed, but $(some_function) did not change.
Alan H. almost 13 years

I have seen code that tests to see if window.onload is defined, and if so, refers to it in a temp variable, then "calls" that variable from within the new window.onload.
fabb almost 13 years

In Chrome, document.addEventListener didn't work, but window.addEventListener did.
Philipp Michalski over 3 years

I assume you mean RegisterClientScriptBlock?
JulienVan about 2 years

Nice, just don't forget to add ");" after the "}"
Kartikeya_M about 2 years

Thanks for pointing that out @JulienVan. Have edited it.