Wait for jQuery to be loaded

waitForJquery.js

var checker = 0;

function jqueryLoaded() {
  clearInterval(checker);
  console.log("jquery is loaded!");
}

function waitForJquery() {
	if (window.jQuery) {
    		jqueryLoaded();
	} 
    	if(checker === 0) {
    		checker = window.setInterval(checkJquery, 100);
    	}
}	

waitForJquery();