//alert(document.getElementById("monitasize"));
size  = "お使いのパソコンのモニターは、<br />";
size += "<span class=\"size\">";
size += window.screen.width + "</span>ピクセル × ";
size += "<span class=\'size\'>";
size += window.screen.height + "</span>ピクセル<br />";
size += "です。"
document.getElementById("monitasize").innerHTML = size;