这是因为您要将事件绑定到准备就绪的文档上。您必须使用委托才能使其正常工作。就像在上一样。这是因为.header加载时不在页面上的页面上。因此，没有附加事件。

It's because you are binding the event on document ready. You have to use a delegate in order for this to work. Like on. It's because .header isn't on the page on the page when it's loaded. So no event is attached.

您的代码应与以下内容相似：

Your code should look some along the lines of this:

$('body').on('click','.heading',function(){
     $(this).css('color','red');  
});   

它不必是主体，但是在准备好文档后不会加载的元素，是 .heading 的父级。

It doesn't have to be body, but an element which isn't loaded after document ready, which is a parent of .heading.