Closed Bug 283093 Opened 20 years ago Closed 19 years ago

Javascript function namespace collision with document object (i.e. evaluate)

Categories

(Firefox :: General, defect)

Product:
Firefox
Component:
General
Platform:
x86
Windows XP
Type:
defect
Priority:
Not set
Severity:
normal

Tracking

()

Status:
RESOLVED INVALID

People

(Reporter: gfaron, Assigned: bugzilla)

Details

User-Agent:       Mozilla/5.0 (Windows; U; Windows NT 5.1; en-US; rv:1.7.5) Gecko/20041107 Firefox/1.0
Build Identifier: Mozilla/5.0 (Windows; U; Windows NT 5.1; en-US; rv:1.7.5) Gecko/20041107 Firefox/1.0

  I created a JavaScript function named evaluate() in a script tag and added the
attribute 'onclick="evaluate();"' to a input button in the page.  My evaluate()
function never gets called and it appears that the callout is actually going to
a built-in DOM function.  In order to get my function to fire, I need to either
change the attribute to read onclick="window.evaluate();" or rename my function.
 This apparent namespace collision defies all books to-date on how to write
proper Javascript, since there's never a mention of keywords like this that you
cannot use for your function name.  I consider this a bug since I do not have to
prefix my callouts when there is not a name collision, like
"window.myHomeMadeFxn()", which can be called just fine without referencing the
window object.
  If I want to call a function on the document object, I should have to
specifally call "document.evaluate();".  But at the very least, functions
authored in the current HTML should have precedence over built-in functions of
the same name.

Reproducible: Always

Steps to Reproduce:
1. Write a JavaScript function named "evaluate" which alerts some text and add
it to the head of the HTML document:
<head>
  <script type="text/javascript">
function evaluate() { alert("Boo!"); }
  </script>
</head>

2. Add <input type="button" value="Click" onclick="evaluate();" /> to the body
of the HTML document.

3. Click the button and notice that no alert occurs.

Actual Results:  
Nothing.  Nothing visible anyway.  It probably ran the DOM method of the same
name, which produced no visible differences to detect.

Expected Results:  
My function should have ran, which would have popped up an alert box with the
message "Boo!"

I'm classifying this Bug as "Normal", though I can understand an argument can be
made for "Minimal".  The mitigating factor here is the sheer quantity of pages
that are already written on the web that may use some "reserved" name and
therefore do not function as expected.
This is not a bug. I don't remember where is it specified, but for scripts that
are put directly in an on-something attribute, the scope chain is modified as
follows: {current element, document, global}.
Yep. This is invalid.  Try calling "write()" in an event handler and see what happens in all browsers.
Status: UNCONFIRMED → RESOLVED
Closed: 19 years ago
Resolution: --- → INVALID
You need to log in before you can comment on or make changes to this bug.