About object's property name

How to add a property to an object when the property na开发者_JS百科me come from a var?

var obj={};
var propName="realName";
obj.propName; //wrong
obj."realName"; //wrong

You can use square bracket notation:

var obj = {};
var propName = "realName";
obj[propName] = "foo";  // Same as `obj.realName = "foo";`