==(或 !=)運算子如果在執行上需要的話,會自動將類型轉換。 ===(或 !==)運算子則不會執行轉換。===(或 !==)用來比較數值和類型,相較於 == 更來的快速。(jsPref

[10] ==  10      // is true
[10] === 10      // is false

'10' ==  10      // is true
'10' === 10      // is false

 []  ==  0       // is true
 []  === 0       // is false

 ''  ==  false   // is true but true == "a" is false
 ''  === false   // is false