How to move cursor at first character positon using jquery mask plugin?

Question

I have searched a lot and found out same kind of question but not exactly same and didn't find satisfactory answer. So thought, Should ask that more specific. Using Jquery mask plugin, I would like my cursor at the beginning always no matter which positon I click. If I click into that textbox, cursor should be at the beginning. with my below code. wherever I click into the textbox, cursor gets that particular positon. How to avoid that?

 <asp:TextBox ID="tbMobile" CssClass="ContactNumber" runat="server" onfocus="GetPhoneMask();" MaxLength="15" placeholder="555-555-5555" ValidationGroup="Application"></asp:TextBox>

function GetPhoneMask() {
        $(".ContactNumber").mask("999-999-9999", { autoclear: false });
    }

Updated:

Answer 1

Live link https://dotnetfiddle.net/Gipb8h

I changed the phone class name.

<%@ Page Title="Home Page" Language="C#" MasterPageFile="~/Site.Master" AutoEventWireup="true" CodeBehind="Default.aspx.cs" Inherits="WebFormsPW._Default" %>

<asp:Content ID="BodyContent" ContentPlaceHolderID="MainContent" runat="server">
    <script src="https://ajax.googleapis.com/ajax/libs/jquery/3.3.1/jquery.min.js"></script>
    <script src="https://cdnjs.cloudflare.com/ajax/libs/jquery.mask/1.14.16/jquery.mask.js"></script>
    <script type="text/javascript">
        $(function () {
            $('.phone_us').mask('(000) 000-0000');
        })
        //took out
        //function GetPhoneMask() {
        //    $(".ContactNumber").mask("999-999-9999", { autoclear: false });
        //}
    </script>
    <%--    took out onfocus="GetPhoneMask();"--%>
    <asp:TextBox ID="tbMobile" CssClass="phone_us" runat="server" MaxLength="15" placeholder="555-555-5555" ValidationGroup="Application"></asp:TextBox>
</asp:Content>