HTML
<asp:Button ID="Button3" runat="server" OnClick="Alert" Text="Button" />
<asp:TextBox ID="TextBox1" onkeypress = "GetKeyCode(event)" runat="server"></asp:TextBox>
JavaScript
function GetKeyCode(evt) {
debugger;
var keyCode;
if (evt.keyCode == 13) {
__doPostBack('Button3', '');
}
}
C#
protected void Alert(object sender, EventArgs e)
{
ClientScript.RegisterClientScriptBlock(this.GetType(), "alert", "alert('hi')", true);
}