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Escape in eval function on Single Quotation

Posted on 2006-07-07
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Last Modified: 2008-03-10
Try these two sample scripts:

This works:
<script>
var boys = 'He said \'howdy\', I said \'hi\'.' // nesting single quotes within single quotes
</script>
<a href="javascript:alert(boys)">Show me the string</a>

This does not work:
<script>
var boys = eval("'He said \'howdy\', I said \'hi\'.'") // nesting single quotes within single quotes
</script>
<a href="javascript:alert(boys)">Show me the string</a>

Why is this? Does not eval handle escape singel character?
And what should I put instead of \' in the eval function to make it work?

Thank you,
Best regards,
Marius
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Question by:traelnes
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7 Comments
 
LVL 2

Expert Comment

by:vikrant4u2
ID: 17057510
Hi Marius,

try this
<script>
var val='He said \'howdy\', I said \'hi\'.';
var boys = eval("val"); // nesting single quotes within single quotes
</script>
<a href="javascript:alert(boys)">Show me the string</a>

regards,
vikrant
0
 
LVL 22

Expert Comment

by:Ivo Stoykov
ID: 17057519
Hello traelnes,

because \' itself is eval again and after eval("'") you've get single quote that have to be evaled again and you get unterminated string constant.

Why you have to eval this? just concatenate...

HTH

I
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LVL 63

Accepted Solution

by:
Zvonko earned 2000 total points
ID: 17057693
Escape chars has to be escaped in eval():

       var boys = eval("'He said \\'howdy\\', I said \\'hi\\'.'");

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Author Comment

by:traelnes
ID: 17057957
Thank you Zvonko for this. It works.

Just curious about what ivostoykov mean by concatenate?
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LVL 63

Expert Comment

by:Zvonko
ID: 17058099
You are welcome.
Let us wait and see what concatenate trick comes along ;-)
0
 

Author Comment

by:traelnes
ID: 17066600
No Concentate. Ok, Zvonko, you are the winner!
0
 
LVL 63

Expert Comment

by:Zvonko
ID: 17067556
:)
Thanks.
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