compare validator--- for password checking

regular expression validator---for checking like email format

compare validator--- for password checking

regular expression validator---for checking like email format

Range validator---checking for dates etc

WebForm_OnSubmit() Js method is tied to form's submit event.

Here is what is inside WebForm_OnSubmit() -
function WebForm_OnSubmit() {
if (typeof(ValidatorOnSubmit) == "function" && ValidatorOnSubmit() == false)  return false;
return true;
}

ValidatorOnSubmit() method will inturn call ValidatorCommonOnSubmit() if the control that caused postback have "CausesValidation" set.

ValidatorCommonOnSubmit() is the one responsibile to check if all the validators are valid.