Convert form data to object with jQuery

formData.js

  (function($) {
    $.fn.formData = function(this) {
      var input = "input[name], select[name], textarea[name]";
      if(this.is(input)) {
        if(this.is("input[type='checkbox'], input[type='radio']")
          return this.is(":checked") ? this.val() : undefined;
        else if(this.is("input[type='number']"))
          return Number(this.val());
        else
          return this.val();
      } else if(this.is("form")) {
        var data = {};
        this.eq(0).find(input).not(":disabled")
          .filter("[name$='[]']").each(function() { // convert [] fields to arrays like php
            var name = $(this).attr("name");
            name = name.substring(0, name.length - 2);
            if(!data[name])
              data[name] = [];
            var val = $(this).formData();
            if(val != undefined)
              data[name].push(val);
          }).end()
          .not("[name$='[]']").each(function() {
            var name = $(this).attr("name");
            data[name] = $(this).formData() || data[name]; // if the name appears multiple times (eg for radio buttons), don't override a value with null
          });
        return data;
      }
    }
   })(jQuery);