function idfare(from, to) {
	//alert("From "+ from + " to " +to );
	// If the destination are the same 
	if (from == to) { 
		alert("From "+ from + " to " +to + " is not a valid destination!");
		}
	
	else { // Different destination, test the journey and return the id_fare coresponding to the trip ( database ID ...)
	  		
			
			switch(from){

				case "Heathrow":
						switch(to){
										// Airport Airport
										case "Gatwick":
											document.getElementById('booking').portto.value = 1;
											break;
										case "Stansted":
											document.getElementById('booking').portto.value = 2;
											break; 
										case "Luton":
											document.getElementById('booking').portto.value = 3; 
											break;						
										case "City":
											document.getElementById('booking').portto.value = 4;
											break;
										// Airport - Port 
										case "Southampton":
											document.getElementById('booking').portto.value = 11;
											break;
										case "Harwich":
											document.getElementById('booking').portto.value = 1;
											break;
										case "Dover":
											document.getElementById('booking').portto.value = 6;
											break;
										default: 
											break;							
										}
							
						break; 

				case "Gatwick":
						switch(to){
											// Airport - Airport
										case "Heathrow":
											document.getElementById('booking').portto.value = 5;
											break;
										case "Stansted":
											document.getElementById('booking').portto.value = 6;
											break; 
										case "Luton":
											document.getElementById('booking').portto.value = 7; 
											break;						
										case "City":
											document.getElementById('booking').portto.value = 8;
											break;
										// Airport - Port 
										case "Southampton":
											document.getElementById('booking').portto.value = 12;
											break;
										case "Harwich":
											document.getElementById('booking').portto.value = 2;
											break;
										case "Dover":
											document.getElementById('booking').portto.value = 7;
											break;
										default: 
											break;		
										}
						break;

				case "Stansted":
						switch(to){
											// Airport - Airport
										case "Heathrow":
											document.getElementById('booking').portto.value = 9;
											break; 
										case "Gatwick":
											document.getElementById('booking').portto.value = 10;
											break;						
										case "Luton":
											document.getElementById('booking').portto.value = 11; 
											break;
										case "City":
											document.getElementById('booking').portto.value = 12;
											break;
										// Airport - Port 
										case "Southampton":
											document.getElementById('booking').portto.value = 13;
											break;
										case "Harwich":
											document.getElementById('booking').portto.value = 3;
											break;
										case "Dover":
											document.getElementById('booking').portto.value = 8;
											break;
										default: 
											break;
										}
						break;

				case "Luton": 
						switch(to){
											// Airport - Airport
										case "Heathrow":
											document.getElementById('booking').portto.value = 13; 
											break;	
										case "Gatwick":
											document.getElementById('booking').portto.value = 14;
											break;
										case "Stansted":
											document.getElementById('booking').portto.value = 15;
											break; 
										case "City":
											document.getElementById('booking').portto.value = 16;
											break;
										// Airport - Port 
										case "Southampton":
											document.getElementById('booking').portto.value = 14;
											break;
										case "Harwich":
											document.getElementById('booking').portto.value = 4;
											break;
										case "Dover":
											document.getElementById('booking').portto.value = 9;
											break;
										default: 
											break;		
										}
						break;

				case "City":
						switch(to){
											// Airport - Airport
										case "Heathrow":
											document.getElementById('booking').portto.value = 17;
											break;
										case "Gatwick":
											document.getElementById('booking').portto.value = 18;
											break;
										case "Stansted":
											document.getElementById('booking').portto.value = 19;
											break; 						
										case "Luton":
											document.getElementById('booking').portto.value = 20; 
											break;
										// Airport - Port 
										case "Southampton":
											document.getElementById('booking').portto.value = 15;
											break;
										case "Harwich":
											document.getElementById('booking').portto.value = 5;
											break;
										case "Dover":
											document.getElementById('booking').portto.value = 10;
											break;
										default: 
											break;		
										} 
						break;
				
				case "Southampton":
						switch(to){
										// Port - Airport 
										case "Heathrow":
											document.getElementById('booking').portto.value = 11;
											break;
										case "Gatwick":
											document.getElementById('booking').portto.value = 12;
											break;
										case "Stansted":
											document.getElementById('booking').portto.value = 13;
											break; 						
										case "Luton":
											document.getElementById('booking').portto.value = 14; 
											break;
										case "City":
											document.getElementById('booking').portto.value = 15;
											break;
										default: 
											break;	
											}
						break;
			
				case "Harwich":
						switch(to){
										// Port - Airport
										case "Heathrow":
											document.getElementById('booking').portto.value = 1;
											break;
										case "Gatwick":
											document.getElementById('booking').portto.value = 2;
											break;
										case "Stansted":
											document.getElementById('booking').portto.value = 3;
											break; 						
										case "Luton":
											document.getElementById('booking').portto.value = 4; 
											break;
										case "City":
											document.getElementById('booking').portto.value = 5;
											break;
										default: 
											break;
										}
						break;
			
				case "Dover":
						switch(to){
										// Port - Airport
										case "Heathrow":
											document.getElementById('booking').portto.value = 6;
											break;
										case "Gatwick":
											document.getElementById('booking').portto.value = 7;
											break;
										case "Stansted":
											document.getElementById('booking').portto.value = 8;
											break; 						
										case "Luton":
											document.getElementById('booking').portto.value = 9; 
											break;
										case "City":
											document.getElementById('booking').portto.value = 10;
											break;
										default: 
											break;	
										}
						break;
				
				default: 
						break;		
					
				
				}
		}
}