Split by Caps in Javascript

Use RegExp-literals, a look-ahead and [A-Z]:

console.log(
  // -> "Hi My Name Is Bob"
  window.prompt('input string:', "HiMyNameIsBob").split(/(?=[A-Z])/).join(" ")  
)

You can use String.match to split it.

"HiMyNameIsBob".match(/[A-Z]*[^A-Z]+/g) 
// output 
// ["Hi", "My", "Name", "Is", "Bob"]

If you have lowercase letters at the beginning it can split that too. If you dont want this behavior just use + instead of * in the pattern.

"helloHiMyNameIsBob".match(/[A-Z]*[^A-Z]+/g) 
// Output
["hello", "Hi", "My", "Name", "Is", "Bob"]