这个演示，在输入时，是不需要与服务端交互，只有全部输入完毕之后，用户点铵钮才进行验证。因此在这里，写Javascript来实现即可。
js:
<script type="text/javascript">
function JumpToNextTextBox(currentTxtBox, nextTextBoxID) {
if (currentTxtBox.value.length >= 5) {
document.getElementById(nextTextBoxID).focus();
}
}
</script>
Html code:
License Key:
<asp:TextBox ID="Number1" runat="server" onkeyup="JumpToNextTextBox(this, 'Number2')" Width="65"></asp:TextBox>
-
<asp:TextBox ID="Number2" runat="server" onkeyup="JumpToNextTextBox(this, 'Number3')" Width="65"></asp:TextBox>
-
<asp:TextBox ID="Number3" runat="server" onkeyup="JumpToNextTextBox(this, 'Number4')" Width="65"></asp:TextBox>
-
<asp:TextBox ID="Number4" runat="server" onkeyup="JumpToNextTextBox(this, 'Number5')" Width="65"></asp:TextBox>
-
<asp:TextBox ID="Number5" runat="server" MaxLength ="5" Width="65"></asp:TextBox>
