Set ASP.Net TextBox value while typing in another using jQuery

Hi vereato,

Please refer below sample code.

HTML

<div>
    <asp:TextBox ID="TextBox1" runat="server" onkeyup="SetTextBox()"></asp:TextBox>
    <asp:TextBox ID="TextBox2" runat="server"></asp:TextBox>
    <asp:TextBox ID="TextBox3" runat="server"></asp:TextBox>
</div>
<script type="text/javascript" src="https://ajax.googleapis.com/ajax/libs/jquery/1.8.3/jquery.min.js"></script>
<script type="text/javascript">
    function SetTextBox() {
        var txt1 = $("[id*=TextBox1]").val();
        $("[id*=TextBox2]").val(txt1);
        $("[id*=TextBox3]").val(txt1);
    }
</script>

Screenshot