MaxLength does not work on Input type (TextMode) Number in ASP.Net

I need to delimit the capture to 5 characters of a Textbox BootStrap form-control and use size and maxlength the same 5 and it doesn't work

This is my code:

<div class = "col-xs-6">
    <asp:TextBox class = "form-control" ID = "txtInventory" name = "txtInventory" runat = "server" TextMode = "Number" Height = "27px" size = "5" MaxLength = "5"> </ asp : TextBox>
</div>

How can I make it so that the capture is restricted to 5 characters?

First of all, Thanks.

Greetings.