How to check that a page is valid using javascript.

<input type="submit" value="Submit" onclick"ValidatePage();" />

<script type="text/javascript">

function ValidatePage() {

if (typeof (Page_ClientValidate) == 'function') {
Page_ClientValidate();
}

if (Page_IsValid) {
// do something
alert('Page is valid!');
}
else {
// do something else
alert('Page is not valid!');
}
}

</script>