native code attached to onblur/onfocus event handler

[wolverine]

Hi All,

In Mozilla Firefox, to onblur and onfocus event of each and every
html element, the browser itself will attach a native event handler. I
mean if you type, 'javascript:alert(window.blur)' in the address bar
of Firefox browser, you can see a 'function ....' . That is a Firefox
browser defined handler.

Now assume that web developer also attach event handlers to 'onblur'
events eg: 'window.blur=f3()'

Is there any way to check if the event handler is a browser attached
handler OR a web developer attached event handler ?

Regards,
Kiran.

 

[David Mark]

Hi All,

In Mozilla Firefox,  to onblur and onfocus event of each and every
html element, the browser itself will attach a native event handler. I

Do tell.

mean if you type, 'javascript:alert(window.blur)' in the address bar
of Firefox browser, you can see a 'function ....' . That is a Firefox
browser defined handler.

Is it? Not unexpectedly, IE shows the same thing.

Now assume that web developer also attach event handlers to 'onblur'
events eg: 'window.blur=f3()'

That is not an event handler (or even a known property) and unless f3
is a factory function, the right side is wrong too. Perhaps you meant
"window.onblur = f3;"?

Is there any way to check if the event handler is a browser attached
handler OR a web developer attached event handler ?

In other words, you want to know if a property (e.g. onblur) of an
element has been set by another script? There is no standard way to
do this. If you need to support just a few browsers and they all
return the same toString results, then you could look for the string
you saw in the alert. Better yet, figure out a way to factor this
decision out of the system.

 

[wolverine]

Do tell.


Is it?  Not unexpectedly, IE shows the same thing.




That is not an event handler (or even a known property) and unless f3
is a factory function, the right side is wrong too.  Perhaps you meant
"window.onblur = f3;"?




In other words, you want to know if a property (e.g. onblur) of an
element has been set by another script?  There is no standard way to
do this.  If you need to support just a few browsers and they all
return the same toString results, then you could look for the string
you saw in the alert.  Better yet, figure out a way to factor this
decision out of the system.

Thanks a lot.

Sorry for posting that stupid a question in the groups. I was confused
and thought 'window.blur' is a event handler for 'blur' event on
window.