1.事件
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<title>Document</title>
<style>
#div{
width:200px;
height:200px;
background:yellow;
position:absolute;
}
</style>
</head>
<body>
<div id="div"></div>
<script>
var oDiv=document.getElementById("div")
oDiv.onmousedown=function(ev){
var disX=ev.clientX-oDiv.offsetLeft
var disY=ev.clientY-oDiv.offsetTop
//注意onmousemove在onmousedown发生之后才有可能发生;onmouseup同理
oDiv.onmousemove=function(ev){
oDiv.style.left=ev.clientX-disX+'px'
oDiv.style.top=ev.clientY-disY+'px'
oDiv.onmouseup=function(){
oDiv.onmouseup=null
oDiv.onmousemove=null
}
}
}
</script>
</body>
</html>
2.ajax请求
var oAjax=new XMLHttpRequest()
oAjax.open('GET','a.txt?t='+new Date().getTime(),true)
oAjax.send()
oAjax.onreadystatechange=function(){
if(oAjax.readyState==4){
if (oAjax.status == 200) {
alert(oAjax.responseText)
var oBjax=new XMLHttpRequest()
oBjax.open('GET','b.txt?t='+new Date().getTime(),true)
oBjax.send()
oBjax.onreadystatechange=function(){
if(oBjax.readyState==4){
if (oBjax.status == 200) {
alert(oBjax.responseText)
}
else{
alert('读取b.txt失败')
}
}
}
}
else{
alert('读取a.txt失败')
}
}
}
