"JavaScript advanced Programming" Reading notes (iii)

operator

increment and decrement operators

 var  num1 = 2;  var  num2 = 20;  var  num3 =--num1 + num2; //  equals  var  num4 = num1 + num2; //  equals  var  num1 = 2;  var  num2 = 20;  var  num3 = num1--+ num2; //  var  num4 = num1 + num2; //  equals  

The root of the difference is that the
The num3 is calculated using the original value of NUM1 (2) to complete the addition calculation, while the NUM4 uses the descending value (1).

"JavaScript advanced Programming" Reading notes (iii)