Answers for "include js file"

linking a script .js

<script type="text/javascript" src="path-to-javascript-file.js"></script>

include other js files in a js file

document.writeln("<script type='text/javascript' src='Script1.js'></script>");
document.writeln("<script type='text/javascript' src='Script2.js'></script>");

javascript include a js file from another

// jQuery
$.getScript('/path/to/imported/script.js', function()
{
    // script is now loaded and executed.
    // put your dependent JS here.
});

How to add js file to a site through url

var jsFile = document.createElement("script");
jsFile.src = "homePage.js";  // it can be path also  "{themes('/scripts/homePage.js')}"
document.body.appendChild(jsFile);  //append it as src to body