function get_wh()
{
    var frameHeight=640;
    if (self.innerHeight)
	frameHeight = self.innerHeight;
    else if (document.documentElement && document.documentElement.clientHeight)
        frameHeight = document.documentElement.clientHeight;
    else if (document.body)
        frameHeight = document.body.clientHeight;
    return frameHeight;
} 
var wheight=get_wh();
function tblresize()
{
    if(document.getElementById("maintbl").clientHeight < wheight)
    {
       document.getElementById("tdpage").style.height=wheight-304+"px";
    }
}