//Code taken from http://guymal.com/mycode/100_percent_iframe/ function resize_iframe() { var height=window.innerWidth;//Firefox if (document.body.clientHeight) { height=document.body.clientHeight;//IE } //resize the iframe according to the size of the //window (all these should be on the same line) document.getElementById("glu").style.height=parseInt(height- document.getElementById("glu").offsetTop-8)+"px"; } // this will resize the iframe every // time you change the size of the window. // window.onresize=resize_iframe; //Instead of using this you can use: // //*******************************************************************************************