SCode Image Reload
Sometimes the numbers on SCodePlugin-generated CAPTCHA image are not easy to read. And rather than refreshing the whole page, it would be nice to reload only the image and generate a new / more readable code.
In order to give this a go, I modified the comment form on Melbourne photoblog and added a short Javascript code to refresh the image source. You can try it yourself on this form, just click the text “Generate another code” and wait shortly for the image to be reloaded with a new code.
I have updated the Usage sample code on SCode Plugin wiki page with this improvement.
As a side note, I found a problem where modifying img.src value via anchor tag’s onclick attribute does not work on IE 6 and the image will just disappear, while it works just fine on Firefox 2 and Opera 8.5 .
function reloadSCode() {
var scodeImage = document.getElementById("scodeImage");
scodeImage.src="$BLOJSOM_BLOG.getBlogBaseURL()/captcha?flavor=kink&t=" + (new Date()).getMilliseconds();
}
<a href="javascript: void(0);" onclick="reloadSCode();">Generate another code</a>.
After some mucking around, I found out that the function call must be made from the href attribute. This works on the browsers mentioned above.
<a href="javascript: reloadSCode();">Generate another code</a>.
Them browsers better implement proper Javascript standard before doomsday comes.
Trailing Comma Within JSON’s Array
I was debugging an AJAXy app which uses JSON as the data format, and it was fine with Firefox but not with Internet Explorer. After further debugging, the culprit turned out to be trailing commas within the data.
{"foo": {
"bar": [
{"id": "1", "url": "http://www.hostA.com"},
{"id": "2", "url": "http://www.hostB.com"},
] }}
theObject.foo.bar.length returns 2 in Firefox, but it returns 3 in Internet Explorer. The solution was obviously to remove the last comma.
I’m guessing the problem is more to Javascript array.length which is handled differently between browsers.
Update: HTML comments embedded within what’s supposed to be JSON’s data will be ignored by Firefox, while they will cause failure during eval in Internet Explorer.