Problems of __dopostback implementation in ASP.net 1.x

ASP.net 1.x's client side postback script is this:
<!--
function __doPostBack (Eventtarget, eventargument) {
var theform;
if (Window.navigator.appName.toLowerCase (). IndexOf ("Netscape") >-1) {
Theform = document.forms["Form1"];
}
else {
Theform = document. Form1;
}
Theform.__eventtarget.value = Eventtarget.split ("$"). Join (":");
Theform.__eventargument.value = eventargument;
Theform.submit ();
}
-->
It is to submit through Form.submit (). There is a problem, form.onsubmit events will not be triggered, so that some client side validation script will be bypassed. In asp.net 2.0, the problem was fix. For ASP.net 1.x, as far as I know, SP1 did not solve the problem. We can use the following code to solve this problem:
String mydopostback = @ "
<script language= "JavaScript" >
<!--
function __mydopostback (Eventtarget, eventargument) {
var theform;
if (Window.navigator.appName.toLowerCase () indexOf ("Netscape") >-1) {
Theform = document.forms["" Form1 ""];
}
else {
Theform = document. Form1;
}
Theform.__eventtarget.value = Eventtarget.split ("$"). Join (":");
Theform.__eventargument.value = eventargument;
if ((typeof (Theform.onsubmit) = = "function") && Theform.onsubmit ()!=false) {
Theform.submit ();
}

}
__doPostBack = __mydopostback
-->
</script> ";
RegisterStartupScript ("Mydopostback", mydopostback);