Cannot read property 'value' of null

Uncaught TypeError: Cannot read property ‘value’ of null
at HTMLButtonElement. (messagedetail-add.html?employeeNum=3a442cf6ff6c4d9893854cf80cbb42a1:381)
at Function.c (layui.js:2)
at n.each (layui.js:2)
at Array. (layui.js:2)
at n.each (layui.js:2)
at HTMLButtonElement.n.event.n.event (layui.js:2)
at HTMLButtonElement.d (VM5357 form.js:2)
at HTMLDocument.dispatch (VM5370 jquery.min.js:3)
at HTMLDocument.q.handle (VM5370 jquery.min.js:3)

解决思路：

1.检查自己的id、追加append里面的id有没有写错