getElementsByClassName() returns a nodeList HTMLCollection*. You are trying to operate directly on the result; you need to iterate through the results. function change_boxes() { var boxes = document.getElementsByClassName(‘boxes’), i = boxes.length; while(i–) { boxes[i].style.backgroundColor = “green”; } } * updated to reflect change in interface
var iframe = $(‘iframe’); // or some other selector to get the iframe $(‘[tokenid=’ + token + ‘]’, iframe.contents()).addClass(‘border’); Also note that if the src of this iframe is pointing to a different domain, due to security reasons, you will not be able to access the contents of this iframe in javascript.
The problem is that you are trying to access the element before it exists. You need to wait for the page to be fully loaded. A possible approach is to use the onload handler: window.onload = function () { var e = document.getElementById(“db_info”); e.innerHTML=’Found you’; }; Most common JavaScript libraries provide a DOM-ready event, though. … Read more
At the point you are calling your function, the rest of the page has not rendered and so the element is not in existence at that point. Try calling your function on window.onload maybe. Something like this: <html> <head> <title></title> <script type=”text/javascript”> window.onload = function(){ var refButton = document.getElementById(“btnButton”); refButton.onclick = function() { alert(‘I am … Read more
You have to put this in a document load event. The DOM hasn’t gotten to abc by the time the script is executed.
I think the easiest approach would be to just check that el is not null before adding an event listener: var el = document.getElementById(‘overlayBtn’); if(el){ el.addEventListener(‘click’, swapper, false); }
Also be careful how you execute the js on the page. For example if you do something like this: (function(window, document, undefined){ var foo = document.getElementById(“foo”); console.log(foo); })(window, document, undefined); This will return null because you’d be calling the document before it was loaded. Better option.. (function(window, document, undefined){ // code that should be taken … Read more
document.all is a proprietary Microsoft extension to the W3C standard. getElementById() is standard – use that. However, consider if using a js library like jQuery would come in handy. For example, $(“#id”) is the jQuery equivalent for getElementById(). Plus, you can use more than just CSS3 selectors.
document.getElementById(‘myframe1’).contentWindow.document.getElementById(‘x’) Fiddle contentWindow is supported by all browsers including the older versions of IE. Note that if the iframe‘s src is from another domain, you won’t be able to access its content due to the Same Origin Policy.
Anyway, this method seems to be quite poorly documented, and In fact, the sources I come across don’t even give it a mention […] Reliance on implicitly-declared global variables aside, the lack of documentation is a great reason not to use it. The apparent promotion of id values into global variables isn’t standards compliant (the … Read more