Take a look at ASP.NET Validation in Depth and Java script page validation Page_clientValidate()
This function's purpose is to verify the validity of the page. It returns false if any validator is not valid, otherwise it returns true.
if (Page_ClientValidate()) {
// Page is Ok
//Submit it To The Server
return true
} else {
//Page is Not Valid
//Return False
return false
}
You might be missing some validation settings on your validator or encountering another error related to JavaScript.
You can manually validate as follows:
<script type="text/javascript" language="javascript>
/* Manual client-side validation of Validator Groups */
function fnJSOnFormSubmit() {
var isGrpOneValid = Page_ClientValidate("valGrpOne");
var isGrpTwoValid = Page_ClientValidate("valGrpTwo");
var i;
for (i = 0; i < Page_Validators.length; i++) {
ValidatorValidate(Page_Validators[i]); //this forces validation in all groups
}
//display all summaries.
for (i = 0; i < Page_ValidationSummaries.length; i++) {
summary = Page_ValidationSummaries[i];
//does this summary need to be displayed?
if (fnJSDisplaySummary(summary.validationGroup)) {
summary.style.display = ""; //"none"; "inline";
}
}
if (isGrpOneValid && isGrpTwoValid)
return true; //postback only when BOTH validations pass.
else
return false;
}
Reference:
Page_ClientValidate() with multiple ValidationGroups - how to show multiple summaries simultaneously?
Page_ClientValidate is validating multiple times.