compare text box values

<label>password :
    <input name="password" id="password" type="password" />
</label>
<br>
<label>confirm password:
    <input type="password" name="confirm_password" id="confirm_password" /> <span id='message'></span>


$('#confirm_password').on('keyup', function () {
    if ($(this).val() == $('#password').val()) {
        alert("paasword match");
    } 
    else 
         {
         alert("Not match");
         }
});

function CheckPassword() {

          if (document.getElementById("txtPassword").value == document.getElementById("txtRePassword").value) {

              alert("password match..!!");

          }
          else {
              alert("password doesn't match..!!");
              return false;

          }
      }

<asp:textbox id="txtPassword" runat="server" textmode="Password" "></asp:textbox>
       <asp:textbox id="txtRePassword" runat="server" textmode="Password" "></asp:textbox>
       <asp:button  Text="Check" id="btnCheck" runat="server" onclientclick="CheckPassword()" />

 <asp:textbox id="txtPassword" runat="server" textmode="Password" ></asp:textbox>
       <asp:textbox id="txtRePassword" runat="server" textmode="Password"></asp:textbox>
<asp:button Text="Check" id="btnCheck" runat="server" onclick="btnCheck_Click"/>

public void btnCheck_Click(object sender, EventArgs e)
        {
            if (txtPassword.Text == txtRePassword.Text)
            {
                Response.Write("password Match..!!");
            }
            else
            {
                Response.Write("password doesn't Match..!!");
            
            }
        
        }