In this article I am explaining how to access ASP.Net Validation controls in Client Side languages like JavaScript.
Trigger ASP.Net Validations using JavaScript
UserName: <asp:TextBox ID="txtName" runat="server"></asp:TextBox>
<asp:RequiredFieldValidator ID="valName" ControlToValidate = "txtName"
runat="server" ErrorMessage="*Required" />
<br />
Email: <asp:TextBox ID="txtEmail" runat="server"></asp:TextBox>
<asp:RequiredFieldValidator ID="valEmail" ControlToValidate = "txtEmail"
    runat="server" ErrorMessage="*Required" />
<input id="btnSave" type="button" value="Save" onclick = "VerifyAndSave()" />

Above I am validating two textboxes using ASP.Net RequiredFieldValidators. But since I want the RequiredFieldValidators to perform validation when triggered by JavaScript I am calling the following JavaScript function on click event of the HTML button.
<script type = "text/javascript">
    function VerifyAndSave() {
        if (typeof (Page_ClientValidate) == 'function') {
            Page_ClientValidate();
        }
        if (Page_IsValid) {
            alert("Validations successful");
            //do something
        }
    }
</script>
 
Trigger Grouped ASP.Net Validations using JavaScript
UserName: <asp:TextBox ID="txtName" runat="server"></asp:TextBox>
<asp:RequiredFieldValidator ID="valName" ValidationGroup = "Group1"
    ControlToValidate = "txtName" runat="server" ErrorMessage="*Required" />
<br />
Email: <asp:TextBox ID="txtEmail" runat="server"></asp:TextBox>
<asp:RequiredFieldValidator ID="valEmail" ValidationGroup = "Group1"
    ControlToValidate = "txtEmail" runat="server" ErrorMessage="*Required" />
<br />
City: <asp:TextBox ID="txtCity" runat="server"></asp:TextBox>
<asp:RequiredFieldValidator ID="valCity" ValidationGroup = "Group2"
ControlToValidate = "txtName" runat="server" ErrorMessage="*Required" />
<br />
Country: <asp:TextBox ID="txtCountry" runat="server"></asp:TextBox>
<asp:RequiredFieldValidator ID="valCountry" ValidationGroup = "Group2"
    ControlToValidate = "txtEmail" runat="server" ErrorMessage="*Required" />
<br />
<input id="btnGroup1" type="button" value="Validate Group1"
    onclick = "VerifyAndSave('Group1')" />
<input id="btnGroup2" type="button" value="Validate Group1"
    onclick = "VerifyAndSave('Group2')" />

Above I have placed two Groups of RequiredFieldValidators and two validate these Groups I have placed two HTML Buttons which call the following JavaScript method.
The method below accepts the GroupName as paramters and triggers the validation for the Group
 
<script type = "text/javascript">
    function VerifyAndSave(groupName) {
        if (typeof (Page_ClientValidate) == 'function') {
            Page_ClientValidate(groupName);
        }
        if (Page_IsValid) {
            alert(groupName + "Validations successful");
            //do something
        }
    }
</script>
 
Enable / Disable ASP.Net Validators using JavaScript
UserName: <asp:TextBox ID="txtName" runat="server"></asp:TextBox>
<asp:RequiredFieldValidator ID="valName" ValidationGroup = "Group1"
    ControlToValidate = "txtName" runat="server" ErrorMessage="*Required" />
<br />
Enable Validation: <input type = "checkbox" id = "chk" onclick = "ToggleValidator(this);" />
<br />
<input id="btnSave" type="button" value="Save" onclick = "VerifyAndSave()" />

Here I have placed two ASP.Net Validation Controls that are enabled or disabled using a CheckBox using the below JavaScript functions. If the CheckBox is checked, the Validators are enabled and if it is unchecked the Validators are disabled.
<script type = "text/javascript">
    function VerifyAndSave() {
        if (typeof (Page_ClientValidate) == 'function') {
            Page_ClientValidate();
        }
        if (Page_IsValid) {
            alert("Validations successful");
            //do something
        }
    }
    function ToggleValidator(chk) {
        var valName = document.getElementById("<%=valName.ClientID%>");
        if (chk.checked) {
            ValidatorEnable(valName, true);
        }
        else {
            ValidatorEnable(valName, false);
        }
    }
</script>
 
With this the article comes to an end. You can download the source using the link below.

AccessingASP.NetValidatorsinJavaScript.zip