仿Google和WindowsLive的拖拽

<HTML> 
<HEAD> 
<TITLE> New Document </TITLE> 
<style type="text/css"> 
body 
{ 
    margin:10px; 
}

#dragHelper 
{ 
    position:absolute;/*重要*/ 
    border:2px dashed #000000; 
    background-color:#FFFFFF; 
    filter: alpha(opacity=30); 
}

.normal 
{ 
    position:absolute;/*重要*/ 
    width:300px; 
    #height:10px; 
    border:1px solid #666666; 
    background-color:#FFFFFF; 
}

.over 
{ 
    position:absolute;/*重要*/ 
    width:300px; 
    #height:10px; 
    border:1px solid #666666; 
    background-color:#f3f3f3; 
    filter: alpha(opacity=50); 
}

.dragArea { 
    CURSOR: move; 
}

</style> 
</HEAD>

<BODY oncontextmenu="window.event.returnValue=false"> 
<input type="text" id="evt" name="eventValue" size="40" /> 
<div id="dragHelper" style="display:none"></div> 
<div class="normal" overClass="over" dragClass="normal"> 
    <table width="100%"> 
        <tbody> 
            <tr bgcolor="#CCCCCC" bar="yes"><td>Cobao</td><td dragArea="yes" class="dragArea">........</td><td>- x</td></tr> 
            <tr><td colspan="3">地址:http://www.cobao.cn</td></tr> 
            <tr><td colspan="3">关键字:</td></tr> 
            <tr><td colspan="3">说明:</td></tr> 
        </tbody> 
    </table> 
</div> 
<div class="normal" overClass="over" dragClass="normal"> 
    <table width="100%"> 
        <tbody> 
            <tr bgcolor="#CCCCCC" bar="yes"><td>新浪</td><td dragArea="yes" class="dragArea">........</td><td>- x</td></tr> 
            <tr><td colspan="3">地址:http://www.sina.com.cn</td></tr> 
            <tr><td colspan="3">关键字:</td></tr> 
            <tr><td colspan="3">说明:</td></tr> 
        </tbody> 
    </table> 
</div> 
<div class="normal" overClass="over" dragClass="normal"> 
    <table width="100%"> 
        <tbody> 
            <tr bgcolor="#CCCCCC" bar="yes"><td>网易</td><td dragArea="yes" class="dragArea">........</td><td>- x</td></tr> 
            <tr><td colspan="3">地址:http://www.163.com</td></tr> 
            <tr><td colspan="3">关键字:</td></tr> 
            <tr><td colspan="3">说明:</td></tr> 
        </tbody> 
    </table> 
</div> 
<div class="normal" overClass="over" dragClass="normal"> 
    <table width="100%"> 
        <tbody> 
            <tr bgcolor="#CCCCCC" bar="yes"><td>QQ</td><td dragArea="yes" class="dragArea">........</td><td>- x</td></tr> 
            <tr><td colspan="3">地址:http://www.qq.com</td></tr> 
            <tr><td colspan="3">关键字:</td></tr> 
            <tr><td colspan="3">说明:</td></tr> 
        </tbody> 
    </table> 
</div>

</BODY> 
<SCRIPT LANGUAGE="JavaScript"> 
<!-- 
var dragObjs = [];                        //可以拖拽的元素数组 
var dragObjTops = [];

var dragHelper = document.getElementById("dragHelper");                    //拖拽时位置框 
var dragObj = null;                        //拖拽对象元素 
var dragObjPos = 0;

var dragObjOffset = {left:0,top:0};        //拖拽对象原始位置 
var mouseInDragObjOffset = {x:0,y:0};    //鼠标在拖拽对象中的相对位置

var initHeight = 40;

Number.prototype.NaN0=function(){return isNaN(this)?0:this;}

function getPosition(e){        //获取元素相对文档的绝对位置 
    var left = 0; 
    var top  = 0; 
    while (e.offsetParent){ 
        left += e.offsetLeft; 
        top  += e.offsetTop; 
        e     = e.offsetParent; 
    }

left += e.offsetLeft; 
    top  += e.offsetTop;

return {x:left, y:top};

}

function mouseCoords(ev){        //获取鼠标相对文档的绝对位置 
    if(ev.pageX || ev.pageY){ 
        return {x:ev.pageX, y:ev.pageY}; 
    } 
    return { 
        x:ev.clientX + document.body.scrollLeft - document.body.clientLeft, 
        y:ev.clientY + document.body.scrollTop  - document.body.clientTop 
    }; 
}

function getMouseOffset(target, ev){        //    获取鼠标相对元素的相对位置 
    ev = ev || window.event;

var elementPos    = getPosition(target); 
    var mousePos  = mouseCoords(ev); 
    return {x:mousePos.x - elementPos.x, y:mousePos.y - elementPos.y}; 
}

function mouseDown(ev){ 
    ev = ev || window.event; 
    target = ev.srcElement || ev.target;

if(dragObj){ 
        return; 
    }

var dragArea = false; 
    if(target.getAttribute("dragArea")){ 
        dragArea = true; 
    }

while(!target.getAttribute("isDragObj")){ 
        if(target.tagName=="HTML") 
            break; 
        target = target.parentNode; 
    }

if(dragArea && target.getAttribute("isDragObj")){ 
        dragObj = target; 
        //重写的目的是让当前对象在最上层 
        document.body.removeChild(dragObj); 
        document.body.appendChild(dragObj);

//记录下拖拽对象原始位置 
        dragObjOffset.left = dragObj.style.left; 
        dragObjOffset.top = dragObj.style.top;

dragObj.className = dragObj.getAttribute("overClass"); 
        //鼠标在拖拽对象中的相对位置 
        mouseInDragObjOffset = getMouseOffset(dragObj, ev);

dragHelper.style.left = dragObj.style.left; 
        dragHelper.style.top = dragObj.style.top; 
        dragHelper.style.width = dragObj.offsetWidth; 
        dragHelper.style.height = dragObj.offsetHeight; 
        dragHelper.style.display = "";

//alert(dragObj.offsetWidth+":"+dragObj.clientWidth); 
    } 
}

function mouseUp(ev){ 
    ev = ev || window.event; 
    target = ev.srcElement || ev.target;

if(dragObj){ 
        dragObj.style.left = dragHelper.style.left; 
        dragObj.style.top = dragHelper.style.top;

dragHelper.style.display = "none"; 
        dragObj.className = dragObj.getAttribute("dragClass"); 
        dragObj = null; 
    }

}

function mouseMove(ev){ 
    ev = ev || window.event;

if(dragObj) { 
        var mousePos = mouseCoords(ev); 
         
        /*dragHelper.style.left = dragObjOffset.left; 
        dragHelper.style.top = dragObjOffset.top; 
        dragHelper.style.width = dragObj.offsetWidth; 
        dragHelper.style.height = dragObj.offsetHeight; 
        dragHelper.style.display = "";*/

var windowWidth = document.body.offsetWidth;        //窗口宽度 
        var windowHeight = document.body.offsetHeight;        //窗口高度

//拖拽对象应该所在当前位置 
        var dragObjLeft = mousePos.x - mouseInDragObjOffset.x; 
        var dragObjTop  = mousePos.y - mouseInDragObjOffset.y;

//增加判断，不然拖拽对象拖出浏览器窗口 
        if(dragObjLeft >= 0 && dragObjLeft <= windowWidth - dragObj.offsetWidth - 20) 
            dragObj.style.left = dragObjLeft;

if(dragObjTop >=0) 
            dragObj.style.top = dragObjTop;

repaint(); 
    } 
}

//克隆对象 
function cloneObject(srcObj, destObj){ 
    destObj = srcObj.cloneNode(true); 
}

function makeDraggable(element){ 
    element.setAttribute("isDragObj", "y"); 
}

function repaint(){ 
    for(i=0; i<dragObjs.length; i++){ 
        if(dragObjs[i] == dragObj){ 
            dragObjPos = i; 
            dragObjs[i] = dragHelper; 
            break; 
        } 
    }

if(dragObjPos>0 && parseInt(dragObj.style.top)<parseInt(dragObjs[dragObjPos-1].style.top)){ 
        dragObjs[dragObjPos] = dragObjs[dragObjPos-1]; 
        dragObjs[dragObjPos-1] = dragHelper; 
        dragObjPos = dragObjPos - 1; 
    }

if(dragObjPos<dragObjs.length-1 && parseInt(dragObj.style.top)>parseInt(dragObjs[dragObjPos+1].style.top)){ 
        dragObjs[dragObjPos] = dragObjs[dragObjPos+1]; 
        dragObjs[dragObjPos+1] = dragHelper; 
        dragObjPos = dragObjPos + 1; 
    } 
    paintDragObjs(); 
    dragObjs[dragObjPos] = dragObj;

}

function paintDragObjs(){ 
    var h = 40; 
    for(i=0; i<dragObjs.length; i++){ 
        dragObjs[i].style.left = 20; 
        dragObjs[i].style.top = h; 
        h += dragObjs[i].offsetHeight + 10; 
    } 
}

function openClose(obj){ 
    obj.innerHTML = obj.innerHTML=="-"?"+":"-"; 
    while(obj.tagName != "TBODY"){ 
        obj = obj.parentNode; 
    }

for(i=0; i<obj.childNodes.length; i++){ 
        if(obj.childNodes[i].nodeName == "#text"  
            || obj.childNodes[i].getAttribute("bar")){ continue; } 
        obj.childNodes[i].style.display=obj.childNodes[i].style.display==""?"none":""; 
    }

paintDragObjs(); 
}

document.onmousedown = mouseDown; 
document.onmouseup = mouseUp; 
document.onmousemove = mouseMove;

window.onload = function(){ 
    var objs = document.getElementsByTagName("Div"); 
    for(i=0; i<objs.length; i++){ 
        var item = objs.item(i); 
        //if(i==1)item.style.height=150; 
        if(item.getAttribute("overClass")){ 
            makeDraggable(item); 
            dragObjs.push(item); 
            item.style.left = 20; 
            item.style.top = initHeight; 
            dragObjTops.push(initHeight); 
            initHeight += item.offsetHeight + 10; 
        } 
    }

//    dragHelper = document.createElement('DIV'); 
//    dragHelper.style.cssText = 'position:absolute;display:none;'; 
//    document.body.appendChild(dragHelper); 
} 
//--> 
</SCRIPT> 
</HTML>

[Ctrl+A 全选注:如需引入外部Js需刷新才能执行]

仿Google和WindowsLive的拖拽_javascript技巧