{ thetop : 10 } is a valid object literal. The code will create an object with a property named thetop that has a value of 10. Both the following are the same:

obj = { thetop : 10 };
obj = { "thetop" : 10 };

In ES5 and earlier, you cannot use a variable as a property name inside an object literal. Your only option is to do the following:

var thetop = "top";

// create the object literal
var aniArgs = {};

// Assign the variable property name with a value of 10
aniArgs[thetop] = 10; 

ES6 defines ComputedPropertyName as part of the grammar for object literals, which allows you to write the code like this:

var thetop = "top",
    obj = { [thetop]: 10 };

console.log(obj.top); // -> 10

chrome测试：


ES5