Detailed explanation of JS attribute names with quotes and without quotes

Generally, the attribute name can be quoted or not, and the effect is the same. This article mainly introduces to you the problems and solutions of adding quotes or not adding quotes to attribute names when declaring objects in JS. Friends in need can refer to it. I hope it can help everyone.

var obj = { 
  name  : '你好', 
  'age'  : 1, 
}; 
document.write( obj[&#39;name&#39;] + &#39;<br />&#39; ); 
document.write( obj.age);

Both the above two lines of code can be executed correctly.

If and only if your attribute name is an illegal and weird name, an error will be reported.

var obj = { 
  333 : '这个会报错' 
}; 
document.write( obj.333);

An error is reported at this time.

var obj = { 
  “333”: '这个也会报错' 
}; 
document.write( obj.333);

If the attribute name is a number, it must have double quotes and be accessed with [] square brackets.

var obj = {
  "333": '这个正确'
};
console.log(obj["333"]);

Conclusion: Use legal attribute names, and you can access them using . and [];

If the attribute name is a number, it must be surrounded by "" , and accessed using [] square brackets.

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