jQuery代码的TypeOf问题

Question

I am having an issue with some code...

This is the code:

(function($) {
    $.fn.inc = function(url, transform, post, t) {
        return this.length && url ? this.each(function() {
            t = $(this);
            $.ajax({
                url: url,
                success: function(txt, jqXHR, textStatus) {
                    t.html($.isFunction(transform) ? transform(txt, url) : txt);
                    $.isFunction(post) && post(url, jqXHR, textStatus);
                }
            });
        }) : this;
    };

    $(function() {
    $('[class*="inc:"]').each(function() {
        var match = /inc:(\S+)/.exec(this.className || '');
        if(typeOf(match[1]) != "undefined")
          match && $(this).inc(unescape(match[1]));
    });

  });

})(jQuery);

and on line 18 it's point to this error:

ReferenceError: typeOf is not defined


if(typeOf(match[1]) != "undefined")

What's wrong with the code?

Error pic:

This error points to:

TypeError: a is null

**return (a.ownerDocument || a) !== n && m(a), t(a, b)**

Answer 1

The operator you are looking for is typeof all in lowercase . JavaScript is case sensitive.

And note that it is an operator, not a function, so you don't need the parentheses (although they don't actually hurt).

Note also that the .exec() method can return null , so you need whether match is null before you try to use it as an array:

if (match != null && typeof match[1] != undefined)

Or just:

if (match && typeof match[1] != undefined)

But you shouldn't need to test if match[1] is undefined , because if match itself is not null then that means your regex matched including the substring match. So the following should be OK:

if (match)
  $(this).inc(unescape(match[1]));

Answer 2

typeof is not a function, it's an operator.

You should use it in this way:

if(typeof match[1] != "undefined")

It should be lowercase.

Answer 3

这应该是typeof （小“ O”）