javascript实现测量字符串长度

代码：

var getStrSize = function(str) {
    var d = document.createElement("div");
    d.style.position = "fixed";
    d.id = "getsize";
    d.innerHTML = str;
    document.body.appendChild(d);
    var result = document.getElementById('getsize');
    var size = result.clientWidth;
    document.body.removeChild(d);
    return size;
}