大神给看看为什么我的click事件没触发

Answer 1

js先执行了，但这时候找不到$("#btn")，因为还没有加载，所以触发不了。你写到body的最后或者$(function(){})里面，都是等页面上的元素渲染完了以后再去找，所以找得到，可以触发事件

Answer 2

js  尽量写在最后  而css在head 里引用完成

Answer 3

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Answer 4

你用JQ写事件前提是引入JQ