Brute Force Attack on the Simple XOR Cipher

Instructions:Enter a plaintext sentence in the textfield labeled "Message:" then hit return. A random key is generated and shown in the textfield labeled "Key:". Then all possible keys are applied to the ciphertext created by xor-encrypting the message with the key. The results are shown in the textarea below the message. It is fairly easy to tell by looking at the output what the original key it. Can the simple xor cipher be modified to make it harder to attack?