Firefox may give you a "Warning: Unresponsive script" prompt that says "A script on this page may be busy, or it may have stopped responding. You can stop the script now, or you can continue to see if the script will complete." This article describes why this could happen and possible solutions and workarounds.
This error is telling you that Firefox thinks that a script may be running out of control and would make Firefox hang if nothing is done. The script could be something on a web page you're accessing, in an extension you installed, or even Firefox itself.
Type about:config in the address bar. Ignore warning and click I'll be careful Type script into the filter box Find dom-max_script_run_time Dbl click dom-max_script_run_time New window will open Enter 0 for integer value OK