IE input.value on page refresh
Run this in IE 7,8 or 9.
<!DOCTYPE html>
<html>
<head>
<m开发者_如何学Goeta charset=utf-8>
<title>IE input value</title>
</head>
<body>
<form action="">
<input id="test" type="text" name="username">
</form>
<script>
var input = document.getElementById("test");
alert(input.value);
setTimeout(function() {
alert(input.value);
}, 2000);
</script>
</body>
</html>
If you enter a value manually, then hit "refresh", the first alert is empty, the second alerts whatever you typed, so it seems IE takes a little longer to "auto-populate" the field again.
Question: is anyone else experiencing this and if so: is there a better way than using setTimeout here?
BTW: Firefox alerts what you typed two times (as I would expect).
Yes, this is known IE behaviour.
Unfortunately, browsers implement form value memory differently:
- Mozilla and WebKit replace the HTML value with the remembered value as soon as the element is loaded into the document;
- IE replaces the value when the document content is completely loaded;
- Opera replaces the value just after document content is loaded, possibly after the
loadevent fires onwindow.
(There are also browser differences about under what circumstances a reload causes form fields to be remembered, and browsers with bfcache will cause field memory to happen less as more back/forward navigations bypass page reloading.)
Aggravatingly, that means if you want to write a script that checks form values and updates page content dependent on them reliably, you have to schedule a 0-delay timeout from window.onload—and, if you want it to react faster than onload, before that too (eg. straight away and/or on a poller).
加载中,请稍侯......
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