注意字符串中的 "\"

/*
官网原文：
     JScript allows C-style escaped newlines in string literals; according to ES3 this would be a syntax error for unterminated string constant 
    Example:
*/ 
<script> 
      var s = "this is a \ 
               multiline string"; 
</script> 
/*
    Output: 
            IE: taken as a single string. 
            FF: same as IE Opera: same as IE 
            Safari: same as IE IE eats away the 
IE eats away the  "\" and the character following it. The s.length will evaluate to 34 (this includes the leading blanks in the second line). FF, Opera and Safari emulate IE.
*/