I had to use a for loop to to go through each character in a string but the code is not working properly

These are the instruction for the exercise I am supposed to do:
Start with a prompt that asks the user to enter any string.

Using a for loop, go through each character in the string.

If the string contains the letter A (capital or lowercase), break out of the loop and print the message below to the screen.

If the string does not contain the letter A, print the message below to the screen.

Here is my code

var text= prompt("Enter any string.")
for (var i = 0; i < text.length; i++) {
    if (text[i] === "A")
    {alert("The string contains the letter A.");
}
     if (text[i] === "a")
    {alert("The string contains the letter A.");
}
 else
      {alert("The string does not contain the letter A.");
}
}