Troubleshooting (Script Authors)
If your problem is not listed, please ask on the mailing list.
Changes don't take effect when editing a script
You may be editing your original copy of the script, not the installed copy. Once you create and install a script, you need to follow these steps to make sure you're editing the installed, active copy.
Also, changing the include and exclude rules in the metadata block of the installed script does not do anything, as the script metadata is only accessed during installation. The script must be re-installed (or config.xml edited manually) for these changes to take.
Note: You can change the include and exclude rules in the Manage User Scripts window and those changes will take effect.
Variables change before a GM_xmlhttpRequest or setTimeout callback runs
The request is asynchronous, meaning the rest of the code doesn't wait for it to complete. The
for keeps running as the request loads. When the request for the first link on the page completes and the
onload callback function runs, the
link variable might point to a different link altogether, typically the last one (since the
for loop completes much quicker than the HTTP requests).
One solution is to pass those values that you want unchanged into a function surrounding the request, as arguments. Then they will be in a different scope, and will no longer be changed from the outside.
Solution example with named function: Template:Good samp Solution example with anonymous function:
Solution example with iteration in the "onload" function. Note that this processes each element one by one.
Component not Available errors
These are usually caused by attempting to access an element's event handlers (
onkeydown, etc.) directly, rather than through
addEventListener. GreaseMonkey 0.5 and above require the use of addEventListener. For details, see XPCNativeWrapper.
Form POST data
When using GM_xmlhttpRequest to POST form data, remember to add the Content-Type parameter: