How can I convert:
from:
'\\x3c'
to:
'<';
I tried:
s=eval(s.replace("\\\\", ""));
does not work. How I do this? Thanks in advance!
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3 Answers
Use String.fromCharCode instead of eval, and parseInt using base 16:
s=String.fromCharCode(parseInt(s.substr(2), 16));
answered Aug 24, 2011 at 15:30
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1+1, a shorter alternative would be
String.fromCharCode(+("0"+s.slice(1)));– Andy ECommented Aug 24, 2011 at 15:59 -
@Andy Even shorter:
String.fromCharCode("0"+s.slice(1));Commented Aug 25, 2011 at 6:55 -
@DigitalPlane: of course,
fromCharCodecasts to an int for you! doh! :-)– Andy ECommented Aug 25, 2011 at 8:35
If you're using jQuery, try this: $('<div>').html('\x3c').text()
Else (taken from here)
function htmlDecode(input){
var e = document.createElement('div');
e.innerHTML = input;
return e.childNodes.length === 0 ? "" : e.childNodes[0].nodeValue;
}
One way to do it, which will incur the wrath of people who believe that "eval" is unequivocally evil, is as follows:
var s = "\\x3c";
var s2 = eval('"' + s + '"'); // => "<"
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I wouldn't say
evalis unequivocally evil, but I would say that this isn't really an acceptable use ofeval(since alternative options exist).– Andy ECommented Aug 24, 2011 at 16:08 -
@Andy E: ok, I'll take the bait =) I agree the
String.fromCharCodeis the right way but assuming we have validated the input (e.g. ensured it can only be an escaped character reference) then what's the potential harm in usingevalhere? To me it seems like one of the few times where it is ok.– maericsCommented Aug 24, 2011 at 16:47 -
I wasn't fishing ;-) But since you asked,
evalis not only avoided for its security risks when passed unsanitised values, but also for its poor performance. Althoughevalitself is slow (since it invokes the js compiler), it also makes the code around it slow. The reason for this is, where a compiler would normally make optimizations as it interprets code, it cannot know the result of the eval'd expression and therefore cannot make such optimizations. There are uses foreval, but in the end it's the dev's decision to look at alternative solutions before taking the plunge.– Andy ECommented Aug 25, 2011 at 0:36