jQuery设置间隔在WordPress中不起作用

Question

The anchors in the span tag should change every 5 seconds but nothing happens. I've tested that jQuery works in WordPress with alert("test"); at the top of my js file.

    <div class="img_ad"><span><a class="active"><img src="http://www.test.co.uk/wp-content/uploads/2014/10/client3.png" /></a>
    <a><img src="http://www.test.co.uk/wp-content/uploads/2014/10/client1.png" /></a>
    <a><img src="http://www.test.co.uk/wp-content/uploads/2014/10/client2.png" /></a></span><span></span><span></span>
 </div>

-

jQuery(document).ready(function($) {


  function swapImages(){
      var $active = $('.img_ad').find("span:first").find(".active");
      var $next = ($('.img_ad').find("span:first").find('.active').next().length > 0) ? $('.img_ad').find("span:first").find('.active').next() : $('.img_ad').find("span:first").find('a:first');
      $active.fadeOut(function(){
      $active.removeClass('active');
      $next.fadeIn().addClass('active');
      });
    }

     // Run our swapImages() function every 5secs
      setInterval('swapImages()', 5000);


});

This code doesn't work, i put alert("test"); in the function swapImages() but nothing happens. I think setInterval is not working. How do i solve this?

Answer 1

Just pass the function directly:

setInterval(swapImages, 5000);

Passing a string is not a recommended way.

• Is there ever a good reason to pass a string to setTimeout?

---

Your code doesn't work because swapImages is not a global function. Passing a string to setInterval -- e..g. "swapImages()" -- requires that the function is globally defined ( window.swapImages = function () { ... } ).

(function () {
    function foo() {
        console.log(1);
    }
    setInterval("foo()", 100); // foo is not defined
})();

That's why you have to pass the real function or an anonymous function that will call your function .

For the links from JSFiddle, open the dev tools window (press F12 ) and go to console.

Answer 2

setInterval(function(){
   swapImages()
},5000);

Try this