<code lang="javascript">
//global background color variable 
//set this to change the hover background color
var BACKGROUND_COLOR = '#ffffcc';

function trhover() 
{
	//sets up all rows in all tables to have the hover effect.
	var tables = document.getElementsByTagName("table"), thisTable, thisRow, rowcount=0, tablecount=0;
	while (thisTable = tables[tablecount++]) 
	{
		while (thisRow = thisTable.rows[rowcount++]) 
		{
			thisRow.onmouseover = turnOn;
			thisRow.onmouseout = turnOff;
		}
	}
}
function turnOn() 
{
	//this function sets the row's background color on mouseover
	this.style.backgroundColor = BACKGROUND_COLOR;
}
function turnOff() 
{
	//this function sets the row's background color back to normal
	this.style.backgroundColor = '';
}


//set up the event handlers for the tables when the page loads
function tableInit()
{
	trhover();
}
window.onload = tableInit;</code>