Proper way to calculate your elem1 variable is:

elem1 = ' "#{id:a1_' + i + "1}"+'" ';

Pay attention to single quotation marks. They are necesary to get your double quotation marks into string.
Have a nice day

thanks Tomislav,

I tried te code using an alert and still having the same problem:

the alert results in  ' " " ' (two double_quotes)

var elem1 is in string format. To execute your code written like that, you must use eval() function.

So your full code would be something like this:

elem1 = ' "#{id:a1_' + i + "1}"+'" ';

var fullStringToExecute = "document.getElementById(" + elem1 + ").value";

if (eval(fullStringToExecute) == 0) {.......

Try it and let me know how it goes!

I did the next test, putting the code in a button and try to set the value for field a1_21 to 3

When i send alert(fullStringToExecute) it shows the next string

document.getElementById("").value

It looks like xpages don't understand the special chars like #{:  in a string.

Is it possible that i should use escape chars for those special chars?

I will give it a try using escape chars .

thnx