button_text.js

var getParameterByName = function (name) {
    name = name.replace(/[\[]/, "\\[").replace(/[\]]/, "\\]");
    var regex = new RegExp("[\\?&]" + name + "=([^&#]*)"),
        results = regex.exec(location.search);
    return results == null ? "" : decodeURIComponent(results[1].replace(/\+/g, " "));
}

if(getParameterByName(signup_text) === '1'){

  jQuery('#signup-button').val('Get started');

} else if(getParameterByName(signup_text) === '2') {

  jQuery('#signup-button').val('Sign up now');

}