(function() {
if(typeof(jQuery) == 'undefined') {
window.jQuery = 'loading';
var jq = document.createElement('script');
jq.type = 'text/javascript';
jq.src = 'https://ajax.googleapis.com/ajax/libs/jquery/3.2.1/jquery.min.js';
jq.onload = function() {
console.log('jQuery ' + jQuery.fn.jquery + ' loaded successfully.');
};
jq.onerror = function () {
delete jQuery;
alert('Error while loading jQuery!');
};
document.getElementsByTagName('head')[0].appendChild(jq);
} else {
if (typeof (jQuery) == 'function') {
alert('jQuery (' + jQuery.fn.jquery + ') is already loaded!');
} else {
alert('jQuery is already loading...');
}
}
})()