Javascript in a Included PHP File - php

Question

I have a php file (a form) that includes javascript to check if all inputs are filled. When I view the php file directly the js works perfectly, but when I include the PHP file in another page the javascript no longer works.
My javascript code:
<script type="text/javascript" src="../js/modernizr.js"></script>
<script type="text/javascript">
window.onload = function(){
document.getElementById("topField").setAttribute("autocomplete","off");
}
window.onload = function() {
// get the form and its input elements
var form = document.forms[0],
inputs = form.elements;
// if no autofocus, put the focus in the first field
if (!Modernizr.input.autofocus) {
inputs[0].focus();
}
// if required not supported, emulate it
if (!Modernizr.input.required) {
form.onsubmit = function() {
var required = [], att, val;
// loop through input elements looking for required
for (var i = 0; i < inputs.length; i++) {
att = inputs[i].getAttribute('required');
// if required, get the value and trim whitespace
if (att != null) {
val = inputs[i].value;
// if the value is empty, add to required array
if (val.replace(/^\s+|\s+$/g, '') == '') {
required.push(inputs[i].name);
}
}
}
// show alert if required array contains any elements
if (required.length > 0) {
alert('The following fields are required: ' +
required.join(', '));
// prevent the form from being submitted
return false;
}
};
}
}
</script>

Answer 1

This is an explanation to anyone who finds this question later. In javascript you can only attach a single function to an event handler. If you want to attach more, you need to chain them. Pretty much all javascript framework/libraries has some sort of method to handle event chaining.
Javascript allows you to treat functions like variables. So you can assign an old onload function to a variable, then call it later within the new onload function.
If you are not using a framework, you can do something like this to handle event chaining.
function addLoadEvent(func) {
var oldonload = window.onload;
if (typeof window.onload != 'function') {
window.onload = func;
} else {
window.onload = function() {
if (oldonload) {
oldonload();
}
func();
}
}
}
You would call this with the following:
addLoadEvent(function(){
// Some code here
});