Price validation using jQuery

price.js

// usage: $("#price").priceField();


$.fn.getCaret = function() { // adapted from http://blog.vishalon.net/index.php/javascript-getting-and-setting-caret-position-in-textarea
	var ctrl = this[0];
	var CaretPos = 0;	// IE Support
	if (document.selection) {
		ctrl.focus();
		var Sel = document.selection.createRange();
		Sel.moveStart('character', -ctrl.value.length);
		CaretPos = Sel.text.length;
	} else if (ctrl.selectionStart || ctrl.selectionStart == '0') { // Firefox support
		CaretPos = ctrl.selectionStart;
	}
	return (CaretPos);
};
  
$.fn.priceField = function() {
  $(this).keydown(function(e){
      var val = $(this).val();
      var code = (e.keyCode ? e.keyCode : e.which);
      var nums = ((code >= 96) && (code <= 105)) || ((code >= 48) && (code <= 57)); //keypad || regular
      var backspace = (code == 8);
      var specialkey = (e.metaKey || e.altKey || e.shiftKey);
      var arrowkey = ((code >= 37) && (code <= 40));
      var Fkey = ((code >= 112) && (code <= 123));
      var decimal = ((code == 110 || code == 190) && val.indexOf('.') == -1);
  
      // UGLY!!
      var misckey = (code == 9) || (code == 144) || (code == 145) || (code == 45) || (code == 46) || (code == 33) || (code == 34) || (code == 35) || (code == 36) || (code == 19) || (code == 20) || (code == 92) || (code == 93) || (code == 27);
  
      var properKey = (nums || decimal || backspace || specialkey || arrowkey || Fkey || misckey);
      var properFormatting = backspace || specialkey || arrowkey || Fkey || misckey || ((val.indexOf('.') == -1) || (val.length - val.indexOf('.') < 3) || ($(this).getCaret() < val.length - 2));
  
      if(!(properKey && properFormatting)) {
          return false;
      }
  });
  
  $(this).blur(function(){
	var val = $(this).val();
	if(val === '') {
		$(this).val('0.00');
	} else if(val.indexOf('.') == -1) {
		$(this).val(val + '.00');
	} else if(val.length - val.indexOf('.') == 1) {
		$(this).val(val + '00');
	} else if(val.length - val.indexOf('.') == 2) {
		$(this).val(val + '0');
	}
  });
  
  return $(this);
};

http://milan.adamovsky.com/2010/02/how-to-write-advanced-jquery-plugins.html

Great suggestion!

I jshinted his pattern: http://jsbin.com/eboveq/edit#source
but I don't know if it will work this way, I just didn't like his style.

I might make this into a single plugin when I get time

Well, the thing about jQuery plugins is that you normally don't want return a value; you return the object. Otherwise chaining is broken,

I'm not actually returning a value, that was just a poor choice for a variable name.