Syntax commands

Is there a way to test if a tag/content exists before I try to use it?
I mean, if I try to "findline" a tag that maybe exists maybe not like "Screenwriters" or "Studio" in iTunes website the script abort the process. I don't this behavior.
I just want the command returns nothing.

Is there a way to implement a "foreach" to loop some tag/content?
"Do" doesn't work well, I can't Nest this command.

"Aborted: ERROR(L359/do): nesting of do command not allowed"


try findline "foo" 1 1

The first "1" is to find the first instance of foo from whichever line the parser is currently located. The second "1" tells the parser to go to the end of the document if foo is not found. Following that line, if you have more stuff to parse out, use gotoline 1 to tell the parser to the first line of the document and to continue your web source script.