Variable problem 1

[dle46163]

Ok, I think this will be an easy one...

I'm piecing together a variable like this:
cb=ikey+"_cb";

This variable ends up being the name of some checkboxes in a form. I want to place the variable in the following alert statement but it won't work!

alert(schedule.cb.length);

If I type in the real name of the form element like:
alert(schedule.145_cb.length);
it does work... So I'm clearly not using the correct syntax as the Javascript is using a literal CB instead of the variable CB. Any thoughts?

 

[BabyJeffy]

Something like this help you ?

alert( eval( "schedule." + cb + ".length" ) );

Cheers,
Jeff

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[dle46163]

Perfect, thank you!!

 

[BillyRayPreachersSon]

Or you could avoid the unnecessary use of eval and go for this method instead:

var cbNum = 145;
alert(document.forms['schedule'].elements[cbNum + '_cb'].length);

Hope this helps,
Dan



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[LyndonOHRC]

Question for Dan:

Is the reason for avoiding eval() because the value is already in an array element and a function call is unnecessary or is the there a performance issue with eval()?



Lyndon

---People Remember about 10% of what you say ---They never forget how you made them feel. Covey

 

[BillyRayPreachersSon]

The latter - because of the generic and uncertain nature of the input to eval (from the JS engine's point of view), it is much quicker to avoid the use of it if a more specific method of getting your result is available.



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