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I thought onload ran when the page was loaded, not before…

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May 15.2008

I am having trouble with my onload code running seemingly before the page has loaded. I thought onload was supposed to run once the page had finished loading?? For example,

[CODE]window.onload = countAnchors();

function countAnchors() {

var anchors = document.getElementsByTagName(‘a’);
var numA = anchors.length;
alert(numA);

}[/CODE]

I get 0 when I refresh the page, but 42 when I click a link which runs countAnchors(), as there are actually 42 <a> elements on the page.

Maybe I am wrong in expecting it to wait for the page… I am new to this. If this is working correctly, can you tell me how I can run some code AFTER the page has loaded?

Thanks for any help.

Grape

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JavaScript

4 Comments(s) ↴

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@TeufelMay 15.2008 — I can't tell you why you get that error.

At first, I thought that window.onload is called before the DOM content will be loaded, but document.body.onload = countAnchors() has the same effect.

Using <body onload="countAnchors()"> worked fine for me, but I'd too like to know why only this works.
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@mrhooMay 15.2008 — [B]window.onload = countAnchors();



Reference [/B]the function, don't [B]call [/B]it here.

use window.onload = countAnchors;

or

window.onload =function(){

alert(document.getElementsByTagName('a').length+' links');


}



Calling a function with parentheses following it[B]() [/B]calls the function[B] immediately.

[/B]
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@ProGrapeauthorMay 16.2008 — [B]window.onload = countAnchors();



Reference [/B]the function, don't [B]call [/B]it here.

use window.onload = countAnchors;

or

window.onload =function(){

alert(document.getElementsByTagName('a').length+' links');


}



Calling a function with parentheses following it[B]() [/B]calls the function[B] immediately.

[/B][/QUOTE]

aaaaahhhh thank you very much ?

an easy thing to overlook, at first.

so how would you call a function with parameters? is the only way to do it to write an anonymous wrapper function, like
[CODE]window.onload = function() {
paramFunc(1, true 'param');
}[/CODE]or is there a special notation to reference functions while also giving them parameters?

thanks again!
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@TeufelMay 16.2008 — //you can use the arguments array within a function:

function foobar() { alert(arguments.length) }

foobar("mouse", 1, location, ["xx", "xxx"]);
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