add a script or link element to the head of a html page using javascript

inject script or style element

// a script to add a script link or css link to the head of a html page
function addMyLink(element, url, type, rel, id) {
    var head = document.getElementsByTagName('head')[0]
    var myLink = document.createElement(element)
    if (element === 'script') {
        myLink.src = url
    } else if (element === 'link') {
        myLink.href = url
        if(rel){myLink.rel = rel}
    }
    if(type){myLink.type = type}
    if (id) {myLink.id = id}
    head.appendChild(myLink)
}

// here are examples of usage
// addMyLink('script', 'https://ajax.googleapis.com/ajax/libs/jquery/3.1.0/jquery.min.js')
// addMyLink('script', 'https://ajax.googleapis.com/ajax/libs/jquery/3.1.0/jquery.min.js', 'text/javascript', '', 'myScripts')
// addMyLink('link', 'https://ajax.googleapis.com/ajax/libs/jqueryui/1.12.1/themes/smoothness/jquery-ui.css')
// addMyLink('link', 'https://ajax.googleapis.com/ajax/libs/jqueryui/1.12.1/themes/smoothness/jquery-ui.css', 'text/css', 'stylesheet', 'myStylesheet')
// addMyLink('link', 'https://developers.google.com/_static/f54730da32/images/favicon.png', 'image/vnd.microsoft.icon', 'shortcut icon', 'favicon')