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jQuery.fn.maxLength = function(len)

{

  var maxLengthKeyPress = new Array();

  var maxLengthChange = new Array();

  var appleKeyOn = false;

  //the second argument should be true if len should be based on

  //the maxlength attribute instead of the input

  var useAttr = arguments.length>1 ? arguments[1] : false;

  var handleKeyUp = function(e)

  {

    //if the apple key (macs) is being pressed, set the indicator

    if(e.keyCode==224||e.keyCode==91)

      appleKeyOn = false;

  }

  var handleKeyDown = function(e)

  {

    //if the apple key (macs) is being released, turn off the indicator

    if(e.keyCode==224||e.keyCode==91)

      appleKeyOn = true;

  }

  var handleKeyPress = function(e)

  {  

    //if this keyCode does not increase the length of the textarea value,

    //just let it go

    if(appleKeyOn || (e.charCode==0&&e.keyCode!=13) || e.ctrlKey)

      return;

    //get the textarea element

    var textarea = $(this);

    //if the length should be based on the maxlength attribute instead of the

    //input, use that

    len = useAttr ? parseInt(textarea.attr('maxlength')) : len;

    //get the value of the textarea

    var val = textarea.val();

    //get the length of the current text selection

    var selected = Math.abs(textarea.attr('selectionStart') - textarea.attr('selectionEnd'));

    selected = isNaN(selected) ? 0 : selected;

    //if this is the maximum length

    if(val.length==len && selected<1)

      return false;

    else if(val.length>len && selected<(val.length-len))

      return textarea.val(textarea.val().substring(0,len));

  };

  var handleChange = function(e)

  {

    //get the textarea element

    var textarea = $(this);

    //if the length should be based on the maxlength attribute instead of the

    //input, use that

    len = useAttr ? parseInt(textarea.attr('maxlength')) : len;

    //truncate the textarea to its proper length

    textarea.val(textarea.val().substring(0,len));

  };

  //get the current keyup and change functions

  var removeKeyPress = maxLengthKeyPress[this.selector];

  var removeChange = maxLengthChange[this.selector];

  //remove the keyup and change functions from any matched elements in case

  //a maxlength was previously set and a new one is being set

  this.die('keypress', removeKeyPress);

  this.die('change', removeChange);

  if(len==0 && !useAttr)

    return;

  //set the keyup and change functions for this element set and all future

  //elements matching this selector

  this.live('keypress', handleKeyPress);

  this.live('change', handleChange);

  this.live('keydown', handleKeyDown);

  this.live('keyup', handleKeyUp);

  //save the current keyup and change functions so that they can be

  //remove later

  maxLengthKeyPress[this.selector] = handleKeyPress;

  maxLengthChange[this.selector] = handleChange;

  //trigger a keypress event so that the limit will be enforced

  this.keypress();

};

$(function()

{

  //limit the length of all textareas with the maxlength attribute

  //NOTE: setting maxlength on a textarea is NOT valid XHTML. this

  //was added for coders who want to code loosely--not me!

  $('textarea[maxlength]').maxLength(null, true);

});