$(document).ready(function() {
    // On the click of the submit button, start the function
    $("#loadBtn").click(function() {
        // Append the loading image to the div that the content is being loaded within
        $("#content").append('<div class="loading" style="display:block;"></div>');
        // Load the file within the content div
        $(this).load("data.html", function(){
            // Hide the loading image once the content has been loaded
            $(".loading", this).hide();
<input type="submit" id="loadBtn" value="Click Me!" />
<div id="content"></div>