变量中的JavaScript反斜杠（\）导致错误 [英] JavaScript backslash (\) in variables is causing an error

问题描述

在Javascript中，当我在一些变量中添加反斜杠时：

In Javascript, when I put a backslash in some variables like:

var ttt = "aa ///\\\";
var ttt = "aa ///\"; 

Javscript显示错误。

Javscript shows an error.

如果我尝试限制用户输入此字符，我也收到错误：

If I try to restrict user in entering this character, I also get an error:

(("aaa ///\\\").indexOf('"') != -1)

限制用户的反斜杠输入不是一个好策略，因为你必须向用户显示恼人的消息。

Restricting backslashes from user input is not a good strategy, because you have to show an annoying message to the user.

为什么我的反斜杠出错？

Why am I getting an error with backslash?

推荐答案

反斜杠（ \ ）是escape character （以及许多其他类C语言）。这意味着当Javascript遇到反斜杠时，它会尝试逃避例如， \ n 是换行符（而不是反斜杠后跟字母n）。

The backslash (\) is an escape character in Javascript (along with a lot of other C-like languages). This means that when Javascript encounters a backslash, it tries to escape the following character. For instance, \n is a newline character (rather than a backslash followed by the letter n).

为了输出文字反斜杠，你需要转义 it 。那个mea ns \\ 将输出一个反斜杠（而 \\\\ 将输出两个，等等）。 aa /// \的原因不起作用是因为反斜杠转义了（这将打印一个文字引号），因此你的字符串没有正确终止。同样，aa /// \\\将无效，因为最后一个反斜杠再次逃脱报价。

In order to output a literal backslash, you need to escape it. That means \\ will output a single backslash (and \\\\ will output two, and so on). The reason "aa ///\" doesn't work is because the backslash escapes the " (which will print a literal quote), and thus your string is not properly terminated. Similarly, "aa ///\\\" won't work, because the last backslash again escapes the quote.

请记住，对于要输出的每个反斜杠，您需要提供Javascript 两个。

Just remember, for each backslash you want to output, you need to give Javascript two.

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