Question

I have pain-time when making input that only allows float number with jquery library. my code can’t prevent chacacter “.” when it’s becoming first input, can anyone guide me to solve this problem?

$('.filterme').keypress(function(eve) {
   if (    ( eve.which != 46 || $(this).val().indexOf('.') != -1 ) 
        && ( eve.which <  48 || eve.which > 57 ) 
        || ( $(this).val().indexOf('.') == 0) 
      )
   {
       eve.preventDefault();
   }
});​

Answer 1

I filter the first position input with the jQuery Caret plugin. Otherwise, once the dot is typed, it’s already late to check where it was placed. I tried checking for the dot, then deleting the dot, but it does not look nice.

jQuery caret plugin:
http://examplet.buss.hk/js/jquery.caret.min.js

What I did:

http://jsfiddle.net/FCWrE/422/

Try it 🙂

$('.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));
    }
  });
});

<script src="https://ajax.googleapis.com/ajax/libs/jquery/1.4.3/jquery.min.js"></script>
<script src="https://cdnjs.cloudflare.com/ajax/libs/caret/1.0.0/jquery.caret.min.js"></script>
<input type="text" class="filterme">