jquery3.3.1.slim.min.js:2jQuery.Deferredexception:$.postisnotafunctionTypeError:$.postis

原因是用了jquery-3.2.1.slim.min.js，换成jquery-3.2.1.min.js就好了

关于两者的区别

看官方描述：
Sometimes you don’t need ajax, or you prefer to use one of the many standalone libraries that focus on ajax requests. And often it is simpler to use a combination of CSS and class manipulation for all your web animations. Along with the regular version of jQuery that includes the ajax and effects modules, we’ve released a “slim” version that excludes these modules. All in all, it excludes ajax, effects, and currently deprecated code. The size of jQuery is very rarely a load performance concern these days, but the slim build is about 6k gzipped bytes smaller than the regular version – 23.6k vs 30k.
就是去掉了ajax的功能。如果你不需要用到ajax或者使用了独立的第三方ajax库，就可以使用这个jquery.slim.js，这是个瘦身版，而不是什么插件。