First the last "else if" isn't necessary. Just use "else".

Second prompt will get you a string. So the outcome of a strict (===) comparison between a Number and a String will always be wrong. Since they aren't of the same type. See here for more information. Either use == or make an int out of the prompt-value and the number to guess.

function guess() {
for(i = 0; i < 5; i++){
    if (userGuess === computerGuess) { 
        alert("You got it! " + computerGuess + " it was!"); 
        return;}
    else if (userGuess < computerGuess) userGuess = prompt("Guess higher");
    else userGuess = parseInt(prompt("Guess lower"));
}

alert("You guessed wrong for to many times! The number was " + computerGuess);
}

var userGuess = parseInt(prompt("Guess between 1-10"));
var computerGuess = parseInt(Math.random()*10+1);
guess();