AJAX - onreadystatechange ???
onreadystatechange ???
??? ??? ???? ? ?? ?? ?? ??? ???? ???.
readyState? ??? ??? onreadystatechange ???? ??????.
readyState ??? XMLHttpRequest? ?? ??? ?????.
??? XMLHttpRequest ??? ? ?? ??? ?????.
| Property | Description |
|---|---|
| onreadystatechange | ?? ??(?? ?? ??). ?? ReadyState ??? ??? ??? ?????. |
| readyState | XMLHttpRequest? ??? ?????. 0?? 4? ?????.
|
| status | 200: "OK" ????. 404: ???? ?? ? ?? |
onreadystatechange ?????? ?? ??? ??? ??? ??? ? ??? ??? ?????.
readyState? 4?? ??? 200?? ??? ?????? ?????.
Instance
<html>
<head>
<script type="text/javascript">
function loadXMLDoc()
{
var xmlhttp;
if (window.XMLHttpRequest)
{// code for IE7+, Firefox, Chrome, Opera, Safari
xmlhttp=new XMLHttpRequest();
}
else
{// code for IE6, IE5
xmlhttp=new ActiveXObject("Microsoft.XMLHTTP");
}
xmlhttp.onreadystatechange=function()
{
if (xmlhttp.readyState==4 && xmlhttp.status==200)
{
document.getElementById("myDiv").innerHTML=xmlhttp.responseText;
}
}
xmlhttp.open("GET","/asset/demo.ajax.php?dm=txt&act=getfruits",true);
xmlhttp.send();
}
</script>
</head>
<body>
<div id="myDiv"><h2>Let AJAX change this text</h2></div>
<button type="button" onclick="loadXMLDoc()">通過(guò) AJAX 改變內(nèi)容</button>
</body>
</html>??: onreadystatechange ???? ? ??? ?? 5?(0 - 4) ??????. ???????
?? ?? ????
?? ??? ?? ??? ????? ???? ?????.
? ???? ?? AJAX ??? ?? ?? XMLHttpRequest ??? ???? ?? ?? ??? ???? ? AJAX ??? ?? ?? ??? ???? ???.
?? ???? onreadystatechange ???? ??? ? ??? URL? ??? ????? ???(???? ?? ? ??):
Instance
<html>
<head>
<script type="text/javascript">
var xmlhttp;
function loadXMLDoc(url,cfunc)
{
if (window.XMLHttpRequest)
{// code for IE7+, Firefox, Chrome, Opera, Safari
xmlhttp=new XMLHttpRequest();
}
else
{// code for IE6, IE5
xmlhttp=new ActiveXObject("Microsoft.XMLHTTP");
}
xmlhttp.onreadystatechange=cfunc;
xmlhttp.open("GET",url,true);
xmlhttp.send();
}
function myFunction()
{
loadXMLDoc("/asset/demo.ajax.php?dm=txt&act=getfruits",function()
{
if (xmlhttp.readyState==4 && xmlhttp.status==200)
{
document.getElementById("myDiv").innerHTML=xmlhttp.responseText;
}
});
}
</script>
</head>
<body>
<div id="myDiv"><h2>Let AJAX change this text</h2></div>
<button type="button" onclick="myFunction()">通過(guò) AJAX 改變內(nèi)容</button>
</body>
</html>
