为什么在公用文件夹中找不到我的JavaScript文件？

Question

I was trying to make my first web and I had the following route in my node.js code:

app.get("/contact_form", function(req, res){
    res.render("new_contact");
});

new_contact was including correctly my javascript file and I was doing that with:

<script type="text/javascript" src="scripts/jquery.min.js"></script>

Now I have changed my route to:

app.get("/contact_form/new", function(req, res){
    res.render("new_contact");
});

And it stopped working; I had to change the including with a / before scripts to make it work again:

<script type="text/javascript" src="/scripts/jquery.min.js"></script>

Please, could someone explain me thoroughly what it is going on? I have taken a look to several answers and websites but all explanations are very vague kind of: 1. The slash means the root. 2. Without the slash is a relative path

And so son.

Thank you in advance.

Answer 1

If you have the url: https://localhost/contact_form , then a relative path ( src="scripts/jquery.min.js" ) will look for the jquery using:

https://localhost/scripts/jquery.min.js

Once you made the change, you had this url: https://localhost/contact_form/new . If you continue to use the relative path, the browser will look for jquery using:

https://localhost/contact_form/scripts/jquery.min.js

Which wouldn't work, because it isn't there. It is at the root .

So changing to the root path ( src="/scripts/jquery.min.js" ) will always start from the root path (just after the domain):

https://localhost/scripts/jquery.min.js