简单拖拽的实现

mutongwu

浏览: 450097 次
性别:
来自: 广州

最近访客更多访客>>

lxswfc

xjg9083

oszerone

micai_1234

博主相关

博客

微博

相册

留言

关于我

文章分类

社区版块

存档分类

博客分类：

JavaScript

IE JavaScript UP

来源：《Javascript权威指南第五版》

<body onload="init();">
<!-- Define the element to be dragged -->
<div style="position:absolute; left:100px; top:100px; width:250px;
            background-color: white; border: solid black;">
<!-- Define the "handle" to drag it with. Note the onmousedown 
 attribute. 
 -->
<div style="background-color: gray; border-bottom: dotted black;cursor:move;
            padding: 3px; font-family: sans-serif; font-weight: bold;"
     onmousedown="drag(this.parentNode, event);">
Drag Me  
</div>
<!-- Content of the draggable element -->
<p>This is a test. Testing, testing, testing.<p>This is a test.<p>Test.
</div>
<div id="zoomDiv"><img id="pic" src="/img/1.jpg" style="width:200px;height:200px;" /></div>
</body>

/**
 * Drag.js: drag absolutely positioned HTML elements.
 *
 * This module defines a single drag( ) function that is designed to be called
 * from an onmousedown event handler. Subsequent mousemove events will
 * move the specified element. A mouseup event will terminate the drag.
 * If the element is dragged off the screen, the window does not scroll.
 * This implementation works with both the DOM Level 2 event model and the
 * IE event model.
 *
 * Arguments:
 *
 *   elementToDrag: the element that received the mousedown event or
 *     some containing element. It must be absolutely positioned. Its
 *     style.left and style.top values will be changed based on the user's
 *     drag.
 *
 *   event: the Event object for the mousedown event.
 **/
function drag(elementToDrag, event) {
    // The mouse position (in window coordinates)
    // at which the drag begins
    var startX = event.clientX, startY = event.clientY;

    // The original position (in document coordinates) of the
    // element that is going to be dragged. Since elementToDrag is
    // absolutely positioned, we assume that its offsetParent is the
    // document body.
    var origX = elementToDrag.offsetLeft, origY = elementToDrag.offsetTop;

    // Even though the coordinates are computed in different
    // coordinate systems, we can still compute the difference between them
    // and use it in the moveHandler( ) function. This works because
    // the scrollbar position never changes during the drag.
    var deltaX = startX - origX, deltaY = startY - origY;

    // Register the event handlers that will respond to the mousemove events
    // and the mouseup event that follow this mousedown event.
    if (document.addEventListener) {  // DOM Level 2 event model
        // Register capturing event handlers
        document.addEventListener("mousemove", moveHandler, true);
        document.addEventListener("mouseup", upHandler, true);
    }
    else if (document.attachEvent) {  // IE 5+ Event Model
        // In the IE event model, we capture events by calling
        // setCapture( ) on the element to capture them.
        elementToDrag.setCapture( );
        elementToDrag.attachEvent("onmousemove", moveHandler);
        elementToDrag.attachEvent("onmouseup", upHandler);
        // Treat loss of mouse capture as a mouseup event.
        elementToDrag.attachEvent("onlosecapture", upHandler);
    }
    else {  // IE 4 Event Model
        // In IE 4 we can't use attachEvent( ) or setCapture( ), so we set
        // event handlers directly on the document object and hope that the
        // mouse events we need will bubble up.
        var oldmovehandler = document.onmousemove; // used by upHandler( )
        var olduphandler = document.onmouseup;
        document.onmousemove = moveHandler;
        document.onmouseup = upHandler;
    }

    // We've handled this event. Don't let anybody else see it.
    if (event.stopPropagation) event.stopPropagation( );  // DOM Level 2
    else event.cancelBubble = true;                      // IE

    // Now prevent any default action.
    if (event.preventDefault) event.preventDefault( );   // DOM Level 2
    else event.returnValue = false;                     // IE

    /**
     * This is the handler that captures mousemove events when an element
     * is being dragged. It is responsible for moving the element.
     **/
    function moveHandler(e) {
        if (!e) e = window.event;  // IE Event Model

        // Move the element to the current mouse position, adjusted as
        // necessary by the offset of the initial mouse-click.
        elementToDrag.style.left = (e.clientX - deltaX) + "px";
        elementToDrag.style.top = (e.clientY - deltaY) + "px";

        // And don't let anyone else see this event.
        if (e.stopPropagation) e.stopPropagation( );  // DOM Level 2
        else e.cancelBubble = true;                  // IE
    }

    /**
     * This is the handler that captures the final mouseup event that
     * occurs at the end of a drag.
     **/
    function upHandler(e) {
        if (!e) e = window.event;  // IE Event Model

        // Unregister the capturing event handlers.
        if (document.removeEventListener) {  // DOM event model
            document.removeEventListener("mouseup", upHandler, true);
            document.removeEventListener("mousemove", moveHandler, true);
        }
        else if (document.detachEvent) {  // IE 5+ Event Model
            elementToDrag.detachEvent("onlosecapture", upHandler);
            elementToDrag.detachEvent("onmouseup", upHandler);
            elementToDrag.detachEvent("onmousemove", moveHandler);
            elementToDrag.releaseCapture( );
        }
        else {  // IE 4 Event Model
            // Restore the original handlers, if any
            document.onmouseup = olduphandler;
            document.onmousemove = oldmovehandler;
        }

        // And don't let the event propagate any further.
        if (e.stopPropagation) e.stopPropagation( );  // DOM Level 2
        else e.cancelBubble = true;                  // IE
    }
}

function init(){
    var pic = document.getElementById('pic');
    pic.onmousedown = function(e){
        if(!e)
            e = window.event;
        drag(this,e);
    }
}

分享到：

valueOf 与 toString() | 对web工程打包的简单Ant文件

2010-08-05 15:24
浏览 950
评论(0)
分类:Web前端
查看更多

发表评论

您还没有登录,请您登录后再发表评论

最近访客更多访客>>

博主相关

文章分类

社区版块

存档分类

最新评论

简单拖拽的实现

评论

发表评论

相关推荐

最近访客 更多访客>>

博主相关

文章分类

社区版块

存档分类

最新评论

简单拖拽的实现

评论

发表评论

相关推荐

webpack简单打包PC网站前端资源

grunt构建基于seajs的网站实现

js平滑滚动回到顶部

fis-amd 的使用与修改

scrollMagic 视差与滚动动画GSAP

skrollr-视差滚动动画插件

stellar插件的使用

icon font VS svg font

gulp下静态资源的合并、压缩、MD5后缀

DOMContentLoaded VS onload VS onreadystatechange

简单的css3全屏滚动

jquery插件treetable 的使用

sublime 侧边栏字体大小修改

移动端的“点透”问题

scheme缺少,ie的bug

大整数相加

getBoundingClientRect 跨浏览器实现

window.name 跨域

window.name 跨域

HTML History API

最近访客更多访客>>