The == (or !=) operator performs an automatic type conversion if needed. The === (or !==) operator will not perform any conversion. It compares the value and the type, which could be considered faster (jsPref) than ==.

[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