js_get_pageHeight()

/**
* Gets the page height.
*
* Credit: http://www.quirksmode.org/viewport/compatibility.html
*/
function js_get_pageHeight(){

var y;
var test1 = document.body.scrollHeight;
var test2 = document.body.offsetHeight
if (test1 > test2) // all but Explorer Mac
{
y = document.body.scrollHeight;
}
else // Explorer Mac;
//would also work in Explorer 6 Strict, Mozilla and Safari
{
y = document.body.offsetHeight;
}

return y;

}