The difference between single and double quotes in JavaScript strings

Recently using JavaScript programming, encountering the use of strings

Wrote a little bit of test code

        var str = ' This is Jack ';
        var str2 = "This is Tom";
        var str3 = ' This is ' Rose ';
        var STR4 = "This is ' LiLi '";
        var STR5 = "This is \" "Sun\";
        var STR6 = ' This is \ ' mary\ ';
        var STR7 = "This is \ ' lucy\ '";
        var str8 = ' This is \ ' rooney\ ';
        var STR9 = ' This is \\Ronaldo\\ ';

        Console.log (str);
        Console.log (STR2);
        Console.log (STR3);
        Console.log (STR4);
        Console.log (STR5);
        Console.log (STR6);
        Console.log (STR7);
        Console.log (STR8);
        Console.log (STR9);

Test Results:

This is Jack
This is Tom
This is "Rose"
This is ' LiLi '
This is "Sun"
This is ' Mary '
This is ' Lucy '
This is "Rooney"
This is \ronaldo\

Conclusion:

(1) Use only character strings, single and double quotes without distinction

(2) You can use double quotes directly in a string enclosed in single quotes, and you can use single quotes directly in a string enclosed in double quotes

(3) If double quotes are used in double quotes, you need to escape with a backslash, note "\", and a single quote in the string enclosed in single quotes, and you also need to escape

(4) If you want to use a backslash, enter ' \ \ '