Javascript conflict with WordPress

Question

I got this geolocation working but if I put it in WordPress it stops working. What's wrong with this?

http://jsfiddle.net/spzg5oL8/3/

$.get("http://freegeoip.net/json/", function (response) {
    $("#ip").html("IP: " + response.ip);
    //$("#country_code").html(response.country_code);
    document.getElementsByClassName(response.country_code)[0].style.display = "block";
}, "jsonp");

Answer 1

This will not work in WordPress for one reason (for sure), and another reason (potentially):

First, you cannot use the $ for jQuery in WordPress. WordPress loads jQuery in "no-conflict" mode, which means you have to use jQuery , OR wrap this in a document ready method to "inject" the $ :

 jQuery(function($) {
    $.get("http://freegeoip.net/json/", function (response) {
        $("#ip").html("IP: " + response.ip);
        //$("#country_code").html(response.country_code);
        // Why don't you use jQuery here, for simplicity?
        // $('.' + response.country_code).style('display', 'block');
        document.getElementsByClassName(response.country_code)[0].style.display = "block";
    }, "jsonp");
});

Second, you have to be sure that jQuery is loaded on your WordPress site. Whatever you do, do not just hard-code a link to jQuery in the header of the site, but rather, in the functions.php file for the theme (or plugin) add the below php:

add_action('wp_enqueue_scripts', 'load_my_scripts');

function load_my_scripts() {
    wp_enqueue_script('jquery');
}

Answer 2

Adding to what @cale_b said, you can see the call to jQuery.noConflict(); as the last line of Wordpress's jQuery file:

/wp-includes/js/jquery/jquery.js

I haven't found anything explicitly in the documentation, but seeing it in the code helps to know what's happening.