hi guys

i am using a else if statement in a function, if i use if and else it will work but if i use if else if else it stops working.
here is my function:



Code:
function myOutzone(){
    var vehicleW,vehicleL,answer6;
    vehicleW = document.getElementById("vehicleW").value;
	vehicleL = document.getElementById("vehicleL").value;
    if (vehicleW>=4.5 || vehicleL>=30) {
	answer6 = "3"
	} else if (vehicleW>=3.5 && vehicleW<4.5) || (vehicleL>=25 && vehicleL<30){answer6 = "2"
	}
else if (vehicleW>=2.5&&vehicleW<3.5)||(vehicleL>=19&&vehicleL<25) 
	{
	answer6 = "1"
	} 
else {answer6 = "0"
	}
	document.getElementById("demo4").innerHTML = "answer is: " + answer6;
	} here is my webpage complete:
HTML Code:
<!DOCTYPE html>
<html>
<head>


<p>1.Rigid Vehicle<br>
2. Rigid Vehicle plus Pig Trailer *<br>  
3. Rigid Vehicle plus Dog Trailer - Category A *<br>
(Overall unladen combination length does not exceed 19 m)<br>
4. Rigid Vehicle plus Dog Trailer - Category B*<br>
(Overall unladen combination length exceeds 19 m) <br>
5. Articulated Vehicle (Prime Mover & Single Semi Trailer) *<br> 
6. Low Loader Combination (with or without dolly) *<br> </p>


<p>
Vehicle Type: (1-6) <input type="number" id="selTruck" ><br>
Vehicle Width: <input type="number" id="vehicleW" ><br>
Vehicle Length: <input type="number" id="vehicleL"><br>
Vehicle Height: <input type="number" id="vehicleH"><br>
<br></p>

<button onclick="myClick()">Press Me</button>

<p id="truck"></p>
<p id="demo"></p>
<p id="demo1"></p>
<p id="demo2"></p>
<p id="demo3"></p>
<p id="demo4"></p>
<p> </p>
<p id="demo"></p>
<p id="demo"></p>

<script>
function myClick(){
	myBeacon();
	myTrip();
	myPower();
	mySpeed();
	mySigns();
	myOutzone();
	
}

function myTrip() {
    var selTruck,vehicleW,vehicleL,answer;
	selTruck = document.getElementById("selTruck").value;
    vehicleW = document.getElementById("vehicleW").value;
	vehicleL = document.getElementById("vehicleL").value;
    answer = (selTruck == 1 && vehicleL > 12.5) ||(selTruck == 2 && vehicleL > 22.01)||(selTruck == 3 && vehicleL > 19)||(selTruck == 4 && vehicleL > 25)||(selTruck == 5 && vehicleL > 30) || (selTruck == 6 && vehicleL > 30)? "Yes":"No";
    document.getElementById("truck").innerHTML = "Do you need a Single trip permit: " + answer;
}

function myBeacon() {
    var vehicleW,vehicleL,answer1;
    vehicleW = document.getElementById("vehicleW").value;
	vehicleL = document.getElementById("vehicleL").value;
    answer1 = (vehicleW > 3) ||  (vehicleL > 25)? "Yes":"No";
    document.getElementById("demo").innerHTML = "Do you need a Beacon: " + answer1;
}
function myPower() {
    var vehicleH,answer2;
    vehicleH = document.getElementById("vehicleH").value;
    answer2 = (vehicleH > 4.3)? "Yes":"No";
    document.getElementById("demo1").innerHTML = "Do you need a Western Power permit: " + answer2;
}

function mySpeed() {
    var vehicleW,answer3;
    vehicleW = document.getElementById("vehicleW").value;
    answer3 = (vehicleW > 3.5)? "80":"100";
    document.getElementById("demo2").innerHTML = "Travel Speed is: " + answer3;
}

function mySigns(){
    var vehicleW,vehicleL,answer4;
    vehicleW = document.getElementById("vehicleW").value;
	vehicleL = document.getElementById("vehicleL").value;
    answer4 = (vehicleW>2.5 && vehicleL>25 || (vehicleW<=2.5 && vehicleL>22 && vehicleL<=25))? "Yes":"No";
	answer5 = (vehicleW>2.5 && vehicleL>25) || (vehicleW<=2.5 && vehicleL>22 && vehicleL<=25)? "Yes":"No";
    document.getElementById("demo2").innerHTML = "Front Warning Sign: " + answer4;
	document.getElementById("demo3").innerHTML = "Rear Warning Sign: " + answer5;
}

function myOutzone(){
    var vehicleW,vehicleL,answer6;
    vehicleW = document.getElementById("vehicleW").value;
	vehicleL = document.getElementById("vehicleL").value;
    if (vehicleW>=4.5 || vehicleL>=30) {
	answer6 = "3"
	} else if (vehicleW>=3.5 && vehicleW<4.5) || (vehicleL>=25 && vehicleL<30){answer6 = "2"
	}
else if (vehicleW>=2.5&&vehicleW<3.5)||(vehicleL>=19&&vehicleL<25) 
	{
	answer6 = "1"
	} 
else {answer6 = "0"
	}
	document.getElementById("demo4").innerHTML = "answer is: " + answer6;
	}
	
</script>

</body>
</html>
i am a beginner learning as i go, any help would be greatly appreciated.
cheers