The shift left operator looks at the integer to the left of the operator as a 32-bit binary number.
The number of positions specified by num2 shifts all the bits of num1 to the left.
As the bits are shifted to the left, zeros are filled in on the right.
Because the number can only be 32-bits long, the extra bits on the left are lost.
The 32-bit binary result of the shifting operation is converted to an integer value and returned from the shift left operation.
The result generated from the shift left operator can be quickly calculated by multiplying the number by 2 raised to the x power, where x is the number of positions shifted.
// 2 = 00000000000000000000000000000010
// 8 = 00000000000000000000000000001000
x = 2 << 2;
document.write("2 << 2 = ",x);