We can bind this functionality with text box KeyUp event. So, when type anything this code will change the text box value in uppercase with each keystroke.
Code Snippet:-
<input type="text" id="variable" name="variable" />
<script type="text/javascript"> $(document).ready(function() { $('#variable').keyup(function() { $(this).val($(this).val().toUpperCase()); }); }); </script>