Load Jquery only if undefined
<script type="text/javascript">
(function() {
// Only do anything if jQuery isn't defined
if (typeof jQuery == 'undefined') {
if (typeof $ == 'function') {
// warning, global var
thisPageUsingOtherJSLibrary = true;
}
function getScript(url, success) {
var script = document.createElement('script');
script.src = url;
var head = document.getElementsByTagName('head')[0],
done = false;
// Attach handlers for all browsers
script.onload = script.onreadystatechange = function () {
if (!done && (!this.readyState || this.readyState == 'loaded' || this.readyState == 'complete')) {
done = true;
// callback function provided as param
success();
script.onload = script.onreadystatechange = null;
head.removeChild(script);
};
};
head.appendChild(script);
};
getScript('https://code.jquery.com/jquery-2.1.1.min.js', function () {
if (typeof jQuery == 'undefined') {
// Super failsafe - still somehow failed...
} else {
// jQuery loaded! Make sure to use .noConflict just in case
fancyCode();
if (thisPageUsingOtherJSLibrary) {
// Run your jQuery Code
} else {
// Use .noConflict(), then run your jQuery Code
}
}
});
} else { // jQuery was already loaded
// Run your jQuery Code
};
})
</script>