简易拖拽
<!DOCTYPE HTML>
<html>
<head>
<meta charset="utf-8">
<title>无标题文档</title>
<style>
#div1 {width:200px; height:200px; background:red; position:absolute;}
</style>
<script>
window.onload=function ()
{
var oDiv=document.getElementById('div1');
var disX=0;
var disY=0;
oDiv.onmousedown=function (ev)
{
var oEvent=ev||event;
disX=oEvent.clientX-oDiv.offsetLeft; //拖拽距离
disY=oEvent.clientY-oDiv.offsetTop; //拖拽距离
oDiv.onmousemove=function (ev)
{
var oEvent=ev||event;
oDiv.style.left=oEvent.clientX-disX+'px';
oDiv.style.top=oEvent.clientY-disY+'px';
};
oDiv.onmouseup=function ()
{
oDiv.onmousemove=null;
oDiv.onmouseup=null;
};
};
};
</script>
</head>
<body>
<div id="div1"></div>
</body>
</html>程序问题:鼠标拖拽过快,鼠标指针与拖拽div对象脱离
解决方法:直接给document加事件(因为div对象范围太小,鼠标移动就与拖拽div对象脱离)
将oDiv改成document对象
<!DOCTYPE HTML>
<html>
<head>
<meta charset="utf-8">
<title>无标题文档</title>
<style>
#div1 {width:200px; height:200px; background:red; position:absolute;}
</style>
<script>
window.onload=function ()
{
var oDiv=document.getElementById('div1');
var disX=0;
var disY=0;
oDiv.onmousedown=function (ev)
{
var oEvent=ev||event;
disX=oEvent.clientX-oDiv.offsetLeft;
disY=oEvent.clientY-oDiv.offsetTop;
document.onmousemove=function (ev)
{
var oEvent=ev||event;
oDiv.style.left=oEvent.clientX-disX+'px';
oDiv.style.top=oEvent.clientY-disY+'px';
};
document.onmouseup=function ()
{
document.onmousemove=null;
document.onmouseup=null;
};
};
};
</script>
</head>
<body>
<div id="div1"></div>
</body>
</html>程序问题: FF下，空Div拖拽Bug(残影)
解决方法: 阻止默认事件
<!DOCTYPE HTML>
<html>
<head>
<meta charset="utf-8">
<title>无标题文档</title>
<style>
#div1 {width:200px; height:200px; background:red; position:absolute;}
</style>
<script>
window.onload=function ()
{
var oDiv=document.getElementById('div1');
var disX=0;
var disY=0;
oDiv.onmousedown=function (ev)
{
var oEvent=ev||event;
disX=oEvent.clientX-oDiv.offsetLeft;
disY=oEvent.clientY-oDiv.offsetTop;
document.onmousemove=function (ev)
{
var oEvent=ev||event;
oDiv.style.left=oEvent.clientX-disX+'px';
oDiv.style.top=oEvent.clientY-disY+'px';
};
document.onmouseup=function ()
{
document.onmousemove=null;
document.onmouseup=null;
};
return false; //阻止默认事件(拖动残影)
};
};
</script>
</head>
<body>
<div id="div1"></div>
</body>
</html>防止拖出页面
<!DOCTYPE HTML>
<html>
<head>
<meta charset="utf-8">
<title>无标题文档</title>
<style>
#div1 {width:200px; height:200px; background:red; position:absolute;}
</style>
<script>
window.onload=function ()
{
var oDiv=document.getElementById('div1');
var disX=0;
var disY=0;
oDiv.onmousedown=function (ev)
{
var oEvent=ev||event;
disX=oEvent.clientX-oDiv.offsetLeft;
disY=oEvent.clientY-oDiv.offsetTop;
document.onmousemove=function (ev)
{
var oEvent=ev||event;
var l=oEvent.clientX-disX;
var t=oEvent.clientY-disY;
//修正拖动位置
if(l<0)
{
l=0;
}
else if(l>document.documentElement.clientWidth-oDiv.offsetWidth)
{
l=document.documentElement.clientWidth-oDiv.offsetWidth;
}
if(t<0)
{
t=0;
}
else if(t>document.documentElement.clientHeight-oDiv.offsetHeight)
{
t=document.documentElement.clientHeight-oDiv.offsetHeight;
}
oDiv.style.left=l+'px';
oDiv.style.top=t+'px';
};
document.onmouseup=function ()
{
document.onmousemove=null;
document.onmouseup=null;
};
return false;
};
};
</script>
</head>
<body>
<div id="div1"></div>
</body>
</html>