[Plugin: Promotion Slider] IE8 incompatible

Sorry, I am on a Mac and don’t really see the error message… can you post it?

If you have a page that generates a serious JavaScript error, then it can interfere with the running of other JavaScript on the page. As such, anything that might be causing the error would also be preventing the slider from working. Most commonly, I have found that these types of JavaScript errors are caused by other plugins that are doing something wrong.

So I would recommend that your first task is to test and see if your theme or another plugin might be the source of your issue. If so, great… you have found the issue. If not, then we can take a second look and see if it might be a slider issue. Here is my general guide on troubleshooting plugins. Steps 3 and 4 are what you will want to do.

I’ll get right on that, here’s the Javascript error’s:

Webpage error details

User Agent: Mozilla/4.0 (compatible; MSIE 8.0; Windows NT 6.1; WOW64; Trident/4.0; SLCC2; .NET CLR 2.0.50727; .NET CLR 3.5.30729; .NET CLR 3.0.30729; Media Center PC 6.0; .NET4.0C; MS-RTC LM 8)
Timestamp: Mon, 31 Oct 2011 15:21:13 UTC

Message: Object doesn’t support this property or method
Line: 5973
Char: 5
Code: 0
URI: https://motorplaza.webfactor.nl/wp-content/themes/motorplaza/lightbox/prototype.js

Message: Object doesn’t support this property or method
Line: 5735
Char: 7
Code: 0
URI: https://motorplaza.webfactor.nl/wp-content/themes/motorplaza/lightbox/prototype.js

Message: Object doesn’t support this property or method
Line: 25
Char: 264
Code: 0
URI: https://motorplaza.webfactor.nl/wp-includes/js/jquery/jquery.js?ver=1.4.4

Message: Object doesn’t support this property or method
Line: 7
Char: 3
Code: 0
URI: https://motorplaza.webfactor.nl/wp-content/plugins/promotion-slider/js/promo_slider.js?ver=3.1

I don’t think the prototype one is relevant, I figured I’d just copy all details.

jQuery is the standard JavaScript library for WordPress and having jQuery and Prototype both loaded isn’t generally recommended and can cause issues if done incorrectly. I would actually think that disabling your lightbox plugin would probably help, but that is just a guess.

It looks like the User Agent is being output to your console? This is likely done with console.log(), which causes issues in IE 8 and earlier. Take a look through all your JavaScript files (quite possibly in your theme) and do a search for ‘console.log’. This is testing code that should never make it on a live site due to the browser incompatibilities.

Ah! It was the lightbox plugin causing the problem, I’ll dig through it and see what’s messing it up.

Thanks a million, never would’ve found that myself!