JS - 32 bit integer to bytes

js_integer_to_bytes.js

~$ node
> var calculatedChecksum = 1513135

// Anding an integer with 0xFF leaves only the least significant byte. 
// For example, to get the first byte, we can write "<int value> & 0xFF"
// This is typically referred to as "masking"
> var firstByte = calculatedChecksum & 0XFF 

// 0XFF00 is hexadecimal, We are masking out the lower byte of your number, 
// then bit-shifting all of the bits to the right by 8. 
// Essentially, we are grabbing the most significant byte of your number and seeing what that is.
> var secondByte = (calculatedChecksum & 0XFF00) >> 8 // instead of ">>8" we can do "/256"

> firstByte
175

> secondByte
22