Jquery for check float numbers on keypress event

Script

 <script type="text/javascript">  
     $(document).ready(function () {  
 $('.isFloat').keypress(function(event) {  
  if ((event.which != 46 || $(this).val().indexOf('.') != -1) && (event.which < 48 || event.which > 57)) {  
   event.preventDefault();  
  }  
 });  
  });  
 </script>  

 <asp:TextBox ID="txtTotlaMark" runat="server" pattern="^[0-9 .]{1,}$" class="isFloat" MaxLength="6" required></asp:TextBox>