SO jQuery Fiddle

Test Fiddle mainly for SO Questions jQuery 1.4.3, UI 1.8.5

by Praveen Kumar Purushothaman

HTML

<link rel="stylesheet" href="http://ajax.googleapis.com/ajax/libs/jqueryui/1.8.5/themes/ui-lightness/jquery-ui.css">
<script src="http://examplet.buss.hk/js/jquery.caret.min.js"></script>
<input type="text" class="filterme">

JavaScript

$('.filterme').keypress(function(eve) {
  if ((eve.which != 46 || $(this).val().indexOf('.') != -1) && (eve.which < 48 || eve.which > 57) || (eve.which == 46 && $(this).caret().start == 0) ) {
    eve.preventDefault();
  }
     
// this part is when left part of number is deleted and leaves a . in the leftmost position. For example, 33.25, then 33 is deleted
 $('.filterme').keyup(function(eve) {
  if($(this).val().indexOf('.') == 0) {    $(this).val($(this).val().substring(1));
  }
 });
});