function getWindowHeight() {
    var windowHeight=0;
    if (typeof(window.innerHeight)=='number') {
        windowHeight=window.innerHeight;
    }
    else {
        if (document.documentElement && document.documentElement.clientHeight) {
            windowHeight= document.documentElement.clientHeight;
        }
        else {
            if (document.body && document.body.clientHeight) {
                windowHeight=document.body.clientHeight;
            }
        }
    }
    return windowHeight;
}


function setHeight() {
    if (document.getElementById) {
        var windowHeight=getWindowHeight();
        if (windowHeight>0) {
            var contentElement = document.getElementById('content_div');
            contentElement.style.height = (windowHeight - 375)+'px';
        }
    }
}

window.onload = function() {
    setHeight();
}
window.onresize = function() {
    setHeight();
}