使用事件委托通过 .on()

$(document).on('click','.register-btn',function(){

代替

$('.register-btn').on('click',function(){

由于.register-btn不驻留在DOM(动态元素)上，因此无法直接绑定事件.

Since .register-btn does not reside on the DOM(dynamic element), you cannot bind the event directly.

对于动态元素，语法为:

For dynamic elements, the syntax is:

$(parentselector).on('event', 'selector', yourFunction)

请注意，parentselector必须是Non-dynamic always DOM present element

Note that parentselector needs to be a Non-dynamic always DOM present element