进行onclick操作并在“提交”按钮上提交表单的结果是什么？

Question

Out of curiosity, I was wondering if there is an expected output when you have something like this:

    <input type="submit" onclick="document.formname.submit()">

I was working with a web page that someone created a few years ago and they had something similar to the above, for whatever reason. I was testing the page on the other end of the submit button, which adds things to a mySQL database. I found that it was occasionally adding everything twice, and was doing this more frequently the more items there are in the form.

Now I wonder if there is a way this is expected to work? I mostly just want to make sure that my code on the other side of the submit button is working properly. Why would this sometimes execute everything twice, and sometimes only once?

Answer 1

如果此标记在<form>内，则将表单中的值提交到服务器端，并且取决于标记的action属性