[opencms-dev] Firefox 3.5 script errors in Explorer view -- fixed version of tree.js

[Christian Steinert]

Dear all, dear Achim

I have fixed various issues with the javascript code that displays the 
Explorer tree, to make it work properly with Firefox 3.5.

The updated file is attached. It should work at least with Opencms 7.0.x 
and 7.5.x.
You have to upload it to the folder /system/workplace/resources/commons/ 
of your opencms installation and then publish it.

As noted before, I won't have time to look into other Firefox 3.5 
issues. If further bugs come up for tree.js, I would be willing to take 
another look but if there are still problems in other areas, then it 
would be great, if others could also help to fix them. Alkacon is doing 
a lot, but they can't be expected to always do everything by themselves.

____________

Things that were changed (none of these changes should negatively affect 
other browsers):

- The tree does not seem to hang/freeze anymore after a rewrite of 
function getNodeIdByName. Before, the logic had been a bit complicated 
and the conditions for terminating this functions, were in my opinion a 
bit dubious before when not finding a tree node.

- All access to tree nodes (previously done directly through direct 
array access in the form tree.nodes[ nodeId ]) is now handled by a new 
function getNodeById.
It seems that at least part of the tree problems in Firefox was, that 
tree nodes are usually using numbers as IDs but sometimes, strings that 
contain numbers are used for accessing them. Maybe, Firefox 3.5 is a 
little stricter in such situations, as soon as the JIT is enabled, since 
the JIT will try to impose type information onto javascript variables. 
The new getNodeById function will sanitize input and find tree nodes 
anyway, even if the node index was passed in as a String and not a 
number. All future read access of tree nodes should also be done through 
this function.

- lots of cleanup:
* sanitized all checks for null/undefined - if(foo != null) was changed 
to if(foo); if(foo==null) was changed to if(!foo), both of which are 
much safer
* changed string concatenation so that "+" is at the end of the previous 
line, which is not as nice to read, but a lot safer (javascript will 
automatically insert semicolons in various situations, and therefore, it 
matters a lot, where line breaks are)
* where possible, changed comparisons to use === instead of == which is 
faster and safer. Note that this is not alway possible, because node ids 
can sometimes be numbers and sometimes be strings
* added various missing variable declarations where they had been 
forgotten (undeclared variables are implicitly global in Javascript, 
which can lead to nasty bugs)
* re-ordered functions so that they are always defined before their 
first caller, as advised by jslint.
* fixed all remaining jslint errors

Comments are welcome.

Kind Regards
Christian

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