Question

I’m not too good on the whole JavaScript (I can do some basic validations) but this isn’t my zone

I’ve got a piece of code below that I’m trying to understand what it does, I can read any code and understand a few parts, but this just stumped me.

Here:

function tm_search_click() {
    if (document.getElementById('tm').value == 'Enter your trademark') {
        document.getElementById('tm').style.backgroundColor = '#fcc';
        return false;
    } else {
        window.location = '?tm=' + escape(document.getElementById('tm').value);
        return true;
    }
}
function qs(a) {
    a = a.replace(/[[]/, "\[").replace(/[]]/, "\]");
    var b = "[\?&]" + a + "=([^&#]*)";
    var c = new RegExp(b);
    var d = c.exec(window.location.href);
    return d == null ? "" : decodeURIComponent(d[1]).replace(/+/g, " ")
}
if (qs("tm") != "") {
    tm_trademark = document.getElementById("tm").value = unescape(qs("tm"));
    tm_partner = "migu2008";
    tm_frame_width = 630;
    tm_frame_height = "auto";
    tm_trademark_country_code = "GB";
    tm_css_url = "http://remarqueble.com/api/theme/search_corporate.css";
    document.getElementById("tmLoading").style.display = "block";
    tm_on_search_result = function () {
        document.getElementById("tmLoading").style.display = "none";
        document.getElementById("tmLoaded").style.display = "block"
    }
} else {
    tm_search_method = "none"
}

That is all of it without the <script> tags.

Could I also edit this code so that it searches are made based on what option the user inputs?

Answer 1

I think it works like this (assuming that this is in tags inside html page)

1. Page loads.
2. The script checks if URL has ‘tm’ parameter. If it has, then it sets bunch of tm_.. parameters and callback function. I don’t know how they are used.
3. User clicks something that triggers the tm_search_click
4. Script sets new URL for the page and browser starts loading that
5. Goto step 1.