cursor: move; -- 出现十字

    var oBox = document.getElementById("box");
    var oH2 = oBox.getElementsByTagName("h2")[0];
    var oA = oBox.getElementsByTagName("a")[0];
    var aSpan = oBox.getElementsByTagName("span");
    var disX = disY = 0;
    var bDrag = false;
//鼠标按下, 激活拖拽
    oH2.onmousedown = function (event)
	{		
		var event = event || window.event;
		bDrag = true;
		disX = event.clientX - oBox.offsetLeft;
        disY = event.clientY - oBox.offsetTop;
        return false;
    }
//拖拽开始
    document.onmousemove = function (event) 
    {
        if (!bDrag) return;
        var event = event || window.event;
        var iL = event.clientX - disX;
        var iT = event.clientY - disY;
        var maxL = document.documentElement.clientWidth - oBox.offsetWidth;
        var maxT = document.documentElement.clientHeight - oBox.offsetHeight;

        iL = iL < 0 ? 0 : iL;
        iL = iL > maxL ? maxL : iL;

        iT = iT < 0 ? 0 : iT;
        iT = iT > maxT ? maxT : iT;

        oBox.style.marginTop = oBox.style.marginLeft = 0;
        oBox.style.left = iL + "px";
        oBox.style.top = iT + "px";
        status();
        
        return false
    };
//鼠标释放, 结束拖拽
    document.onmouseup  = function () 
    {
        bDrag = false;
        status()
    };
 //阻止冒泡
    oA.onmousedown = function (event) 
    {
        (event || window.event).cancelBubble = true
    };

//监听状态函数 显示在屏幕上的状态
    function status() 
    {
        aSpan[0].innerHTML = bDrag;
        aSpan[1].innerHTML = oBox.offsetTop;
        aSpan[2].innerHTML = oBox.offsetLeft
    }

    //初始调用
    status()