I have script 

2. <script>
3. jQuery(function($) {
4.       $('#fname').bind("change keyup", function() {
5. var val = $(this).val();
6. var regex = /^\d+$/;
7. if (val.match(regex)) {
8.   $(this).css("background", "red");
9.   val = val.replace(regex, "");
10.   $(this).val(val);
11. }
12.       });
13. });
14. </script>
15. <input type="text" id="fname" name="fname">

This works exactly the opposite of what I want. 

When wrote in the field, will not be allowed characters except numbers and dot once.

It's about writing price.

Thanks.