Why wont this javascript code execute?

/in /by

Why wont this javascript code execute?

<!Doctype html> 
<html> 
<title>JavaScript Tutorial</title> 
<body> 
<script language = "javascript"> 
var cleanCities = ["Cheyenne ","Santa Fe ","Tucson ","Great Falls ","Honolulu"]; 
var cityToCheck = "Tucson"; 
if(cityToCheck === cleanCities[i]) 
{ 
alert("You are clean"); 
} 
</script> 
</body> 
</html> 
it looks logically and syntactically correct so im not sure what im missing.