Javascript parameter

Question

I noticed that when I pass a string like this \[(tan(w)\] as a parameter to a function, the argument when printed in the function I passed it into is [(tan(w)]. Why would the slashes get stripped?

score 2 · Accepted Answer · answered Dec 12 '12 at 15:51

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The slash in a string in any language whose syntax is inherited from C is used to escape other characters. For example if you want to put a double quote (") in your string, you use \"

To put a slash in a string, you have to put a double slash : "\\[(tan(w)\\]"

answered Dec 12 '12 at 15:51

Denys Séguret

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JavaScript is a language of the C family? – Dennis Traub Dec 12 '12 at 15:51
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@DennisTraub Its syntax, yes, just like java, Go, C#, etc. – Denys Séguret Dec 12 '12 at 15:52
I would say "language with C style syntax". – Alnitak Dec 12 '12 at 15:52
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It might somewhat look like a C-based language, but that doesn't make it one. In fact I only started to understand JavaScript once I recognized it's not C-based. – Dennis Traub Dec 12 '12 at 15:54
They're just somewhat related syntaxwise. A lot of the concepts don't translate very well in either direction, but if you know C syntax, it goes a long way toward learning the basic syntax of a bunch of other languages. The concepts in JS, though, came from a whole different place (Scheme, Self, and a few others not even close in syntax). – cHao Dec 12 '12 at 15:54
@DennisTraub I edited to make it clearer but it's not uncommon to speak of the C-family languages when speaking of languages whose syntax is inherited from C. – Denys Séguret Dec 12 '12 at 15:56
@DennisTraub I feel that the mindset of thinking "oh I know, that's just like in " mostly gets you into trouble. I try to understand the semantics of each language anew without letting other languages cloud my judgement. – phant0m Dec 12 '12 at 15:56
If you talk about syntax, I think all languages has implemented escape character, and they're use same character, the `\` – Alfian Busyro Dec 12 '12 at 15:58
@phant0m but it can help you start faster. You probably don't know Go but just looking at [this](http://stackoverflow.com/questions/12462377/selecting-a-function-from-a-list-of-functions-in-golang/12462668#12462668) you can get an idea of the structure of the program. – Denys Séguret Dec 12 '12 at 15:59
@dystroy Sure, I agree on that. – phant0m Dec 12 '12 at 16:04
@arufian: Most, but not all. VB, for example, doubles quotes and (AFAIK) doesn't otherwise use escape characters. And apparently Delphi uses `#xx` (where `xx` is a numeric character code). – cHao Dec 12 '12 at 16:07

score 1 · Answer 2 · answered Dec 12 '12 at 15:51

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Backslash characters are special.

If you want to pass one in a string, and have it preserved, you have to pass two:

"\\[(tan(w)\\]"

answered Dec 12 '12 at 15:51

Alnitak

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score 1 · Answer 3 · answered Dec 12 '12 at 15:51

In a string literal, the \ has special meaning. It means that you're starting an escape sequence meant to represent some character.

If the escape sequence actually has a specified meaning, the new character is substituted for the entire sequence. If not, the slash is just removed.

The escape sequence to include a literal backslash in the resulting string is a backslash followed by another backslash. \\

Javascript parameter

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