Just short note to my self. If getElementById doesn't work, most probably I forgot window.onload, because if page is not loaded yet, and javascript is executed, then my element with ID will not exist. So, html part looks like:

 

<!DOCTYPE html>
<html>

	<head>
		<script type="text/javascript" src="/arrayAssignment.js"></script>
	</head>
	
	<body>
		Variable <strong>A</strong>: <span id='varA'></span>
		<br/>
		<strong>var b = a</strong>: <span id='b=a'></span>
		<br/>
		b.splice(3);
		<br/>
		Variable <strong>A</strong>: <span id='bSplice'></span>
		<br/>
	</body>

</html>

and javascript part should lok something like:

window.onload = function() {
	var a = [];
	var b = [];
	a = [1, 2, 3, 4]
	b = a;
	document.getElementById("varA").innerHTML = a;
	document.getElementById("b=a").innerHTML = b;
	b.splice(3);
	document.getElementById("bSplice").innerHTML = a;
};

This is just short note to myself since I always forget onLoad part :)

It seems that javascript considers array as a pointer, therefore, simple assignment like:

a = b

will not copy values, variable a will just "point out" to variable b.

Consider following example: 

var a = [];
var b = [];
a = [1, 2, 3, 4]
b = a;
b.splice(3);

In this case, variable a will be 1, 2, 3

Full example you can see here.

Solution is something like: 

b = [].concat(a);

Taken from here.

<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html>
   <head>
		<title></title>
		<meta http-equiv="Content-Type" content="text/html; charset=utf-8"/>
		
		<script>
			function errorTimeOut(strInTest) {
				alert('I will wait 10 seconds, but no variables (error: Uncaught ReferenceError: strTest is not defined). ' + strInTest)
			}
			
			function errorAlert() {
				var strTest = "I am here!";
				setTimeout("errorTimeOut(strTest)", 10000);
			}
			
			function correctTimeOut(strInTest) {
				alert('I was waiting 20 seconds, and everything is ok: ' + strInTest)
			}

			function correctAlert() {
				var strTest = "I am here!";
				setTimeout(function() {
					correctTimeOut(strTest)
				}, 20000);
			}
		
			setTimeout(alert('I am fired immediately'), 10000);
			
			errorAlert();
			
			correctAlert();
			
		</script>
	
	</head>
	
	<body>

	</body>
   
</html>

As you can see from previous code, setTimeout(alert('I am fired immediately'), 10000); will not work.

setTimeout("alert('I will wait')", 10000); - this will work, alert under quotes, but you can not pass varibles.

And the code:

function correctAlert() {
	var strTest = "I am here!";
	setTimeout(function() {
		correctTimeOut(strTest)
	}, 20000);
}

Will work properly.

var tableProperties = {
    aoColumns: []
};

for (var i = 0; i < 9; ++i) {

    var obj = {
        _origColumnPosition: i
    };
    tableProperties.aoColumns.push(obj);
}