function getHeight() {
    var box = document.getElementsByTagName('div');
    var heights = new Array();
    var x = -1;
    for (var i = 0; i < box.length; i++) {
        var temp = box[i];
        if(temp.className == 'box_content') {
            x++;
            heights[x] = temp.offsetHeight;
        }
	}
    
    heights.sort(numSort);
    
    for (var i = 0; i < box.length; i++) {
        var temp = box[i];
        if(temp.className == 'box_content') {
            temp.style.height = heights[0] + 'px';
        }
	}
    
}

function numSort(a, b) {
	return (b - a);
}

function initLoad(func)
{	
	var oldonload = window.onload;
	if (typeof window.onload != 'function'){
    	window.onload = func;
	} else {
		window.onload = function(){
		oldonload();
		func();
		}
	}

}

initLoad(getHeight);