318695 - interface freeze if on undefined .style return; no javascript console response

Status: VERIFIED INVALID

(Firefox :: General, defect)

Description

[Alex Seifert]

User-Agent:       Mozilla/5.0 (Macintosh; U; PPC Mac OS X Mach-O; de; rv:1.8) Gecko/20051111 Firefox/1.5
Build Identifier: Mozilla/5.0 (Macintosh; U; PPC Mac OS X Mach-O; de; rv:1.8) Gecko/20051111 Firefox/1.5

When a website which has an undefined return value for 'document.getElementById(id).style.top' or 'document.getElementById(id).style.left' is visited, the interface freezes. There is no response from the tabs nor the toolbar items. The 'X' button on the tabs bar  and the main menu are the only things that work. The website is still usable and the keyboard shortcuts still work. There is also no reaction from the JavaScript Console when this happens. If you open a new window, the interface on the new window works fine.

Reproducible: Always

Steps to Reproduce:
1. Create a blank html page
2. Add at least 2 basic HTML items (i.e. <div> and <a>). Give them IDs.
3. Add a JavaScript function that will respond when you hover the mouse over one of them. In the function, try to get the style.top or the style.left attributes of the other item using its ID in the functions "document.getElementById(id).style.top" or "document.getElementById(id).style.left".
4. In Firefox, open the file you just created. Hover over the item with the function attached to it.

Actual Results:  
The interface freezes only leaving the menus, keyboard shortcuts, and the 'X' button on the tab bar working.

Expected Results:  
The interface should have continued to work correctly.

Build platform
target
powerpc-apple-darwin7.9.0

Build tools
Compiler 	Version 	Compiler flags
cc 	gcc version 3.3 20030304 (Apple Computer, Inc. build 1666) 	-Wall -W -Wno-unused -Wpointer-arith -Wcast-align -Wno-long-long -nostdinc -isystem /Developer/SDKs/MacOSX10.2.8.sdk/usr/include/gcc/darwin/3.3 -isystem /Developer/SDKs/MacOSX10.2.8.sdk/usr/include -F/Developer/SDKs/MacOSX10.2.8.sdk/System/Library/Frameworks -fpascal-strings -no-cpp-precomp -fno-common -I/Developer/SDKs/MacOSX10.2.8.sdk/Developer/Headers/FlatCarbon -pipe
c++ 	gcc version 3.3 20030304 (Apple Computer, Inc. build 1666) 	-fno-rtti -fno-exceptions -Wall -Wconversion -Wpointer-arith -Wcast-align -Woverloaded-virtual -Wsynth -Wno-ctor-dtor-privacy -Wno-non-virtual-dtor -Wno-long-long -nostdinc -nostdinc++ -I/Developer/SDKs/MacOSX10.2.8.sdk/usr/include/gcc/darwin/3.3/c++ -I/Developer/SDKs/MacOSX10.2.8.sdk/usr/include/gcc/darwin/3.3/c++/ppc-darwin -I/Developer/SDKs/MacOSX10.2.8.sdk/usr/include/gcc/darwin/3.3/c++/backward -isystem /Developer/SDKs/MacOSX10.2.8.sdk/usr/include/gcc/darwin/3.3 -isystem /Developer/SDKs/MacOSX10.2.8.sdk/usr/include -F/Developer/SDKs/MacOSX10.2.8.sdk/System/Library/Frameworks -fpascal-strings -no-cpp-precomp -fno-common -fshort-wchar -I/Developer/SDKs/MacOSX10.2.8.sdk/Developer/Headers/FlatCarbon -pipe

Configure arguments
--enable-application=browser --enable-update-channel=release '--enable-optimize=-O2 -g' --disable-debug --disable-tests --enable-update-packaging --enable-static --disable-shared --enable-official-branding --enable-prebinding --with-macos-sdk=/Developer/SDKs/MacOSX10.2.8.sdk --enable-svg --enable-canvas