javascript event 对象的clientX,offsetX,screenX,pageX的区别：
用html5的drag来实现拖拽有兼容性问题，使用拖拽插件代码又很多，而这个拖拽demo代码少，并且兼容所有浏览器，很值得在项目中使用，
css样式如下：
#div1{ width: 100px; height: 100px; background-color: #4D4D4D; position: absolute; cursor: pointer; -webkit-box-shadow: 3px 3px 0px 3px #C7C7C7; box-shadow: 3px 3px 3px 0px #C7C7C7; } #parent{ width: 500px; height: 500px; border: 1px solid #CDCDCD; position: relative; margin: 0 auto; //父级元素设置为： background-color: #F4F4F4; } .postText{ width: 500px; height: 30px;margin: 0 auto; background-color: #F4F4F4; } .postText span{ padding:0px 10px; }
html代码如下：
<div> <div onmousemove="posMove(this.id)"></div> </div> <div> 移动的距离Top：<span></span>Left:<span></span> </div>
js代码及注释如下
function posMove(getdivid) { var oDiv = document.getElementById(getdivid); var oParent = document.getElementById('parent'); var sent = { l: 10, //设置div在父元素的活动范围，10相当于给父div设置padding-left：10; r: oParent.offsetWidth - oDiv.offsetWidth, // offsetWidth:当前对象的宽度， offsetWidth = width+padding+border t: 10, b: oParent.offsetHeight - oDiv.offsetHeight, n: 10 } drag(oDiv, sent); } /** * * @param obj:被拖动的div * @param sent :设置div在容器中可以被拖动的区域 */ function drag(obj,sent){ var dmW = document.documentElement.clientWidth || document.body.clientWidth; var dmH = document.documentElement.clientHeight || document.body.clientHeight; var sent = sent || {}; var l = sent.l || 0; var r = sent.r || dmW - obj.offsetWidth; var t = sent.t || 0; var b = sent.b || dmH - obj.offsetHeight; var n = sent.n || 10; obj.onmousedown = function (ev){ var oEvent = ev || event; var sentX = oEvent.clientX - obj.offsetLeft; var sentY = oEvent.clientY - obj.offsetTop; document.onmousemove = function (ev){ var oEvent = ev || event; var slideLeft = oEvent.clientX - sentX; var slideTop = oEvent.clientY - sentY; if(slideLeft <= l){ slideLeft = l; } if(slideLeft >= r){ slideLeft = r; } if(slideTop <= t){ slideTop = t; } if(slideTop >= b){ slideTop = b; } obj.style.left = slideLeft + 'px'; obj.style.top = slideTop + 'px'; document.getElementById('posTop').innerHTML = slideTop; document.getElementById('posLeft').innerHTML = slideLeft; }; document.onmouseup = function (){ document.onmousemove = null; document.onmouseup = null; } return false; } }
以上就是关于js拖拽效果的实现代码，希望对大家的学习有所帮助。
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