Need Client Side Validation for TextBox if '<' and '>' are used in textbox ASP.NET

问题

Could you please Suggest a client Side Validation for the TextBox in ASP.NET. Needs validation and should not allow user to use '<>'. When text is entered between '<' and '>', it should show validation

回答1:

You can do this using CustomValidator

<asp:TextBox ID="TextBox1" runat="server"></asp:TextBox>
<asp:CustomValidator runat="server" id="customvalidator1"   ControlToValidate="TextBox1" 
EnableClientScript="true" ErrorMessage="Cannot accept- < or >" ClientValidationFunction="jsvalidate" />

below script should be placed in aspx

<script type="text/javascript">
        function jsvalidate(sender, args) {
            debugger;
            var val = document.getElementById('<%=TextBox1.ClientID%>').value;
            if ((val.indexOf('<') !== -1) || (val.indexOf('>') !== -1)) {
                alert("Error");
                args.IsValid = false;
            }
            else
             {
              args.IsValid = true;
              }
        }
    </script>

来源：https://stackoverflow.com/questions/35504083/need-client-side-validation-for-textbox-if-and-are-used-in-textbox-asp-n