resources/jquery/jquery.byteLimit.js

   1 /**
   2  * jQuery byteLimit
   3  *
   4  * @author Jan Paul Posma
   5  */
   6 ( function( $ ) {
   7
   8         /**
   9          * Enforces a byte limit to a textbox, so that UTF-8 entries are not arbitrarily truncated.
  10          */
  11         $.fn.byteLimit = function( limit ) {
  12
  13                 // Default to current attribute value
  14                 if ( limit == null ) {
  15                         limit = this.attr( 'maxLength' );
  16
  17                 // If passed, update/set attribute value instead
  18                 } else {
  19                         this.attr( 'maxLength', limit );
  20                 }
  21
  22                 // Nothing passed and/or empty attribute, return without binding an event.
  23                 if ( limit == null ) {
  24                         return this;
  25                 }
  26
  27                 // We've got something, go for it:
  28                 return this.keypress( function( e ) {
  29                         // First check to see if this is actually a character key
  30                         // being pressed.
  31                         // Based on key-event info from http://unixpapa.com/js/key.html
  32                         // jQuery should also normalize e.which to be consistent cross-browser,
  33                         // however the same check is still needed regardless of jQuery.
  34
  35                         // Note: At the moment, for some older opera versions (~< 10.5)
  36                         // some special keys won't be recognized (aka left arrow key).
  37                         // Backspace will be, so not big issue.
  38
  39                         if ( e.which === 0 || e.charCode === 0 || e.which === 8 ||
  40                                 e.ctrlKey || e.altKey || e.metaKey )
  41                         {
  42                                 return true; //a special key (backspace, etc) so don't interfere.
  43                         }
  44
  45                         var len = $.byteLength( this.value );
  46
  47                         // limit-3 as this doesn't count the character about to be inserted.
  48                         if ( len > ( limit-3 ) ) {
  49                                 e.preventDefault();
  50                         }
  51                 });
  52         };
  53
  54 } )( jQuery );