function divHeight() {
		var divMain = document.getElementById('mainContent');
		var divSidebar = document.getElementById('sidebar1');

		// Get height
        var contentHoogteMain;
		if (navigator.appName == "Microsoft Internet Explorer") {
			contentHoogteMain = divMain.scrollHeight;
		} else {  // Other browser
			contentHoogteMain = divMain.offsetHeight;			
		}

		//alert(contentHoogteMain);

		// zet de hoogte van de sidebar
		divSidebar.style.height = contentHoogteMain+"px";		
	}
	
    onload = divHeight;
    onresize = divHeight;