function init() {
    var source1 = document.getElementById("c_l");
    var source2 = document.getElementById("c_r");
    var target = document.getElementById("mb_c_c");
	var height1=source1.offsetHeight;
	var height2=source2.offsetHeight;
    if (height1>height2) {
		target.style.height = source1.offsetHeight + "px";
	} else {
		if (height1<height2) target.style.height = source2.offsetHeight + "px";
	}
}