i post something into an iframe then read back the contents of the iframe with json parse…so sometimes it’s not a json string Try this: if(response) { try { a = JSON.parse(response); } catch(e) { alert(e); // error in the above string (in this case, yes)! } }
I wrote an article on this issue a while back, Cross Domain AJAX. The easiest way to handle this if you have control of the responding server is to add a response header for: Access-Control-Allow-Origin: * This will allow cross-domain Ajax. In PHP, you’ll want to modify the response like so: <?php header(‘Access-Control-Allow-Origin: *’); ?> … Read more
One trick you can use to increase the number of concurrent connections is to host your images from a different sub domain. These will be treated as separate requests, each domain is what will be limited to the concurrent maximum. IE6, IE7 – have a limit of two. IE8 is 6 if you have a … Read more
You need to check for status 0 (as when loading files locally with XMLHttpRequest, you don’t get a status returned because it’s not from a Webserver) function readTextFile(file) { var rawFile = new XMLHttpRequest(); rawFile.open(“GET”, file, false); rawFile.onreadystatechange = function () { if(rawFile.readyState === 4) { if(rawFile.status === 200 || rawFile.status == 0) { var … Read more
For the record, as far as I can tell, you had two problems: You weren’t passing a “jsonp” type specifier to your $.get, so it was using an ordinary XMLHttpRequest. However, your browser supported CORS (Cross-Origin Resource Sharing) to allow cross-domain XMLHttpRequest if the server OKed it. That’s where the Access-Control-Allow-Origin header came in. I … Read more
The code below demonstrates on how to do this. var http = new XMLHttpRequest(); var url=”get_data.php”; var params=”orem=ipsum&name=binny”; http.open(‘POST’, url, true); //Send the proper header information along with the request http.setRequestHeader(‘Content-type’, ‘application/x-www-form-urlencoded’); http.onreadystatechange = function() {//Call a function when the state changes. if(http.readyState == 4 && http.status == 200) { alert(http.responseText); } } http.send(params); In … Read more
Sounds like the recommended way to do it is to have your server read the Origin header from the client, compare that to the list of domains you would like to allow, and if it matches, echo the value of the Origin header back to the client as the Access-Control-Allow-Origin header in the response. With … Read more
With HTML5 you can make file uploads with Ajax and jQuery. Not only that, you can do file validations (name, size, and MIME type) or handle the progress event with the HTML5 progress tag (or a div). Recently I had to make a file uploader, but I didn’t want to use Flash nor Iframes or … Read more