I get an undefined value. The option tag has a class set to it. Why am I not getting a value back? Html: <select ... ... <看更多>

Pure JS vs jQuery. Pure JavaScript will be significantly faster as you can see by this jsPerf which pits document.getElementByClassName vs the jQuery ... ... <看更多>

Case 1： .prop(name, value) 設定value 值. <input type="checkbox" class ... ... <看更多>

Classes. // jQuery newDiv.addClass('foo') // Vanilla newDiv. ... jQuery $.get('//example.com', function (data) { // code }) // Vanilla var httpRequest = new ... ... <看更多>