change input to upper case

Using Javascript

<asp:TextBox onkeypress="javascript:this.value=this.value.toUpperCase();"  onkeyup="javascript:this.value=this.value.toUpperCase();" ID="TextBox1" runat="server"></asp:TextBox>

Using CSS

<style>

    .uppercase {

    text-transform: uppercase;

}

</style>

<asp:TextBox CssClass="uppercase" ID="TextBox1" runat="server"></asp:TextBox>