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jquery簡單的拖動效果實現原理及示例
<!DOCTYPE html>
<html>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
<title>簡單拖曵原理實例</title>
<style type="text/css">
#drag{width:400px;height:300px;background:url(http://upload.yxgz.cn/uploadfile/2009/0513/20090513052611873.jpg);cursor:move;position:absolute;top:100px;left:100px;border:solid 1px #ccc;}
h2{color:#fff;background: none repeat scroll 0 0 rgba(16, 90, 31, 0.7);color:#FFFFFF;height:40px;line-height:40px;margin:0;}
</style>
<script src="http://ajax.googleapis.com/ajax/libs/jquery/1.7.2/jquery.min.js" type="text/javascript"></script>
<script type="text/javascript">
$(function(){
/*--------------拖曳效果----------------
*原理：標記拖曳狀態dragging ,坐標位置iX, iY
* mousedown:fn(){dragging = true, 記錄起始坐標位置，設置鼠標捕獲}
* mouseover:fn(){判斷如果dragging = true, 則當前坐標位置 - 記錄起始坐標位置，絕對定位的元素獲得差值}
* mouseup:fn(){dragging = false, 釋放鼠標捕獲，防止冒泡}
*/
var dragging = false;
var iX, iY;
$("#drag").mousedown(function(e) {
dragging = true;
iX = e.clientX - this.offsetLeft;
iY = e.clientY - this.offsetTop;
this.setCapture && this.setCapture();
return false;
});
document.onmousemove = function(e) {
if (dragging) {
var e = e || window.event;
var oX = e.clientX - iX;
var oY = e.clientY - iY;
$("#drag").css({"left":oX + "px", "top":oY + "px"});
return false;
}
};
$(document).mouseup(function(e) {
dragging = false;
$("#drag")[0].releaseCapture();
e.cancelBubble = true;
})
})
</script>
</head>
<body>
<div id="drag">
<h2>來拖動我啊</h2>
</div>
</body>
</html>
