Check if Javascript script exists on page

Question

I have a bookmarklet that I\'ve made and it loads a script from my server onto the users current page. However I have an if check in my script that if a condition is not met the

Answer 1

In case working with local and live alternatively.

The exact URL may change. I think the ID method is better.

This is a combination of Two StackOverflow answers.

if (!document.getElementById('your-id')) {
        addScript("your_script_src"); //adding script dynamically
        addCSSFile("your_css_src"); // adding css files
}

function addScript(path) {
        var head = document.getElementsByTagName("head")[0];
        var s = document.createElement("script");
        s.type = "text/javascript";
        s.src = path;
        s.id = "your-id";
        head.appendChild(s);
}

function addCSSFile(path) {
    var head = document.getElementsByTagName("head")[0];
    var s = document.createElement("style");
    s.type = "text/css";
    s.src = path;
    head.appendChild(s);
}