Strange Opera-only JavaScript issue... (related to si-clear-children script)

[jeffbax]

I'm working on a site that requires some overlapping html tables, and one of the issues is making sure that neither overlaps the rest of the site content when growth is unpredictable.

I found a script that accomplishes this task

http://www.shauninman.com/archive/20...nline_absolute

And its quite good actually, the problem is Opera 9+ doesn't seem to want to participate and gives this JavaScript debug error:

JavaScript - file://localhost/Users/Jeff/Desktop/si-clear-children-1.0/clear.html
Inline script thread
Error:
name: TypeError
message: Statement on line 65: Could not convert undefined or null to object
Backtrace:
  Line 65 of linked script file://localhost/Users/Jeff/Desktop/si-clear-children-1.0/si-clear-children.js
    if (! elem.className.match(/\bclear_children\b/))
          Line 47 of linked script file://localhost/Users/Jeff/Desktop/si-clear-children-1.0/si-clear-children.js
    this.clear();
  Line 89 of linked script file://localhost/Users/Jeff/Desktop/si-clear-children-1.0/si-clear-children.js
    SI.ClearChildren.initialize();

The code in question is... and I'll bold the lines

/*--------------------------------------------------------------------------------
 SI.ClearChildren v1.0

 Instructions for use:

 0. Include the following rules in your CSS (IE Win 5 requires `clear_children` to 
	be display: inline; you can use the * html hack--just be sure to hide from IE 
	Mac):

 	.clear_children,.cc_tallest { position: relative; }
	.cc_tallest:after { content: ''; }

 1. Layout your elements using absolute positioning relative to a container with a 
	class of `clear_children` which contains only the absolutely positioned 
	elements (no other inline elements).

 2. This causes the containing element to collapse.

 3. Decide which contained element will be the deepest on the most occasions and 
	assign a class of `cc_tallest`. This will cause the containing element to 
	expand to the height of this element.

 4. Include this file.

 ---------------------------------------------------------------------------------*/
if (!SI) { var SI = new Object(); };
SI.ClearChildren =
{
	control			: null,
	watchInterval	: 50,
	height			: 0,
	initialize		: function()
	{
		// IE Mac chokes on this (width and height assignments in particular). Go fish.
		if (document.createElement && !(document.all && !window.print))
		{
			var c = document.createElement('div'), s = c.style;
			s.position		= 'fixed';
			s.top			= '0';
			s.visibility	= 'hidden';
			s.width			= '1.em';
			s.height		= '1.em';
			this.control = document.body.appendChild(c);
			this.height = 0;
			window.setInterval('SI.ClearChildren.monitor()', this.watchInterval);
		};
		this.clear(); //49
	},
	
	monitor	: function()
	{
		var o = this.height;
		this.height = this.control.offsetHeight;
		if (o != this.height) { this.clear(); };
	},
	
	clear : function()
	{
		if (!document.getElementsByTagName && !document.all) { return; }

		var elems = (document.all) ? document.all : document.getElementsByTagName('*');
		for (var i = elems.length-1; i >= 0; i--)
		{
			var elem = elems[i];
			if (!elem.className.match(/\bclear_children\b/)) { continue; }; //65
			var container = elem;
			var tallest;
			var maxHeight = 0;
			for (var j = 0; j < container.childNodes.length; j++)
			{
				var contained = container.childNodes[j];
				if (contained.nodeType == 1)
				{
					if (contained.offsetHeight > maxHeight)
					{
						maxHeight	= contained.offsetHeight;
						tallest		= contained;
					};
					contained.className = contained.className.replace(/\bcc_tallest\b/, '');
				};
			};
			// Add to the front of the existing classes to appease IE Mac. Save me Jeebus. 
			tallest.className = 'cc_tallest' + ((tallest.className == '') ? '' : ' ' + tallest.className);
		};
	}
};

// Just do it.
SI.ClearChildren.initialize(); //89

IE7, Safari, and Mozilla all work well, but Opera is giving a pain but I'd rather not have to just use a different stylesheet for Opera as a workaround.

You can download more examples with the code pack
http://www.shauninman.com/assets/exa...ildren-1.0.zip

And none seem to work in Opera.

Anyone know what might be the issue?

[Mittineague]

Is your Opera browser identifying itself as Opera?
Tools -> Quick Preferences -> Edit Site Preferences -> Network -> Browser Identification

[Logic Ali]

This is just a guess, but perhaps some elements returned by Opera through document.all have no className. Try changing:

var elems = (document.all) ? document.all : document.getElementsByTagName('*');

to

var elems = document.getElementsByTagName?document.getElementsByTagName('*') : document.all  ;

and

if (!elem.className.match(/\bclear_children\b/))

to

if (elem.className && !elem.className.match(/\bclear_children\b/))

[jeffbax]

No dice, I did that, and removed a line supposedly for IE Mac which gave this error...

JavaScript - file://localhost/Users/Jeff/Desktop/si-clear-children-1.0/clear.html
Inline script thread
Error:
name: TypeError
message: Statement on line 83: Could not convert undefined or null to object
Backtrace:
  Line 83 of linked script file://localhost/Users/Jeff/Desktop/si-clear-children-1.0/si-clear-children.js
    tallest.className = "cc_tallest" + (tallest.className == "" ? "" : " " + tallest.className);
  Line 47 of linked script file://localhost/Users/Jeff/Desktop/si-clear-children-1.0/si-clear-children.js
    this.clear();
  Line 89 of linked script file://localhost/Users/Jeff/Desktop/si-clear-children-1.0/si-clear-children.js
    SI.ClearChildren.initialize();

But now the script just doesn't work
Its on line

tallest.className = 'cc_tallest' + ((tallest.className == '') ? '' : ' ' + tallest.className);

which I assume is where the actually fix is applied dynamically, but it didn't throw errors on the other lines anymore so maybe this is the last hurrah?

*edit*

nm... with those changes it doesn't work in any browsers now.

And yes, Opera is identifying as Opera.

[jeffbax]

Ooh Logic, I tried just your first fix cause thats where the bug started, and it works