参考链接：

问：

1 What is the difference between the below two usages?2 3 document.getElementById('myRadio').checked = "checked";4 and5 6 document.getElementById('myRadio').checked = true;7 For me, both are behaving the same way. But, I am just curious to know why there exist two methods to do the same.8 9 Which one will be the ideal usage? I need to support IE7 and higher versions.

答：

1 document.getElementById('myRadio').checked is a boolean value. It should be true or false2 3 document.getElementById('myRadio').checked = "checked"; casts the string to a boolean, which is true.4 5 document.getElementById('myRadio').checked = true; just assigns true without casting.6 7 Use true as it is marginally more efficient and is more intention revealing to maintainers.

document.getElementById（'myRadio'）。checked是一个布尔值。 这应该是真的或假的

document.getElementById（'myRadio'）。checked =“checked”; 将字符串转换为布尔值，这是正确的。

document.getElementById（'myRadio'）。checked = true; 只是分配true而不投射。

使用true，因为它的效率稍微高一点，而且更有意向维护者展示。

所以设置这种单属性的值为 true 或 false 就对了。