Grade Calculator JavaScript not running

Question

I attempted to create a grade calculator for any value of grades in JavaScript. No parts of the code are executed when the code is run. Is there a blatant error in my code's syntax? Thanks, Ben

var numberofgrades = prompt("How many grades do you want to calculate?");
var countingvalue = 1;
var grades = [0];
var tempgrade = 0;
var averagetotal = 0;
for(i=0;i<numberofgrades;i++;){
if(countingvalue!=numberofgrades){
   var tempgrade= prompt("What is your "+countingvalue"th grade?")
   grades.push(tempgrade);
   countingvalue++;
}
else if(countingvalue==numberofgrades){
    for(var j=1;j=<numberofgrades;j++){
        averagetotal = grades[j]+averagetotal;
    }
}
    alert("Your average grade is: "+(averagetotal/numberofgrades));

Newest edited code-

var numberofgrades = prompt("How many grades do you want to calculate?");
var countingvalue = 1;
var grades = [0];
var tempgrade = 0;
var averagetotal = 0;
for(i=0;i<numberofgrades;i++){
if(countingvalue!=numberofgrades){
   var tempgrade= prompt("What is your "+countingvalue+"th grade?")
   grades.push(tempgrade);
   countingvalue++;
}
else if(countingvalue==numberofgrades){
    for(var j=1;j<=numberofgrades;j++){
        averagetotal = grades[j]+averagetotal;
    }
  }
}
alert("Your average grade is: "+(averagetotal/numberofgrades));

My syntax was just fixed for this issue, and it is now running. I am having problems adding two numbers instead of my program concatenating the values. Thanks for your help, Ben

var averagetotal = (grades[j]+averagetotal);

Here is the whole code.

var numberofgrades = prompt("How many grades do you want to calculate?");
var countingvalue = 0;
var grades = [];
var tempgrade = 0;
var averagetotal = 0;
for(var i=0;i<=numberofgrades;i++){
if(countingvalue!=numberofgrades){
    if(countingvalue==1){
    var tempgrade= prompt("What is your "+(countingvalue+1)+"st grade?");
    grades.push(tempgrade);
    countingvalue++;
}
    else if(countingvalue!=1){
    var tempgrade= prompt("What is your "+(countingvalue+1)+"th grade?");
    grades.push(tempgrade);
    countingvalue++;
    }
}
else if(countingvalue==numberofgrades)
{
    for(var j=0;j<numberofgrades;j++){
        var averagetotal = (grades[j]+averagetotal); // problem line
        alert(j+" "+averagetotal); //checking values
    }
}


}
alert(grades[0]); //just checking values
alert(grades[1]); //checking values
alert(averagetotal);
alert("Your average grade is: "+(averagetotal/numberofgrades));

Answer 1

you have a syntax error. Instead of

for(i=0;i<numberofgrades;i++;)

it should be

for(i=0;i<numberofgrades;i++)

---

also instead of

var tempgrade= prompt("What is your "+countingvalue"th grade?")

it should be

var tempgrade= prompt("What is your "+countingvalue+"th grade?")

---

also instead of

for(var j=1;j=<numberofgrades;j++){

it should be

for(var j=1;j<=numberofgrades;j++){

---

and finally there seems to be a problem with your brackets - you are missing } at the end

Answer 2

try this code

<script>
var numberofgrades = prompt("How many grades do you want to calculate?");
var countingvalue = 1;
var grades = [0];
var tempgrade = 0;
var averagetotal = 0;
for(var i=0;i<numberofgrades;i++){
if(countingvalue!=numberofgrades)
{
   var tempgrade= prompt("What is your "+countingvalue+"th grade?");
   grades.push(tempgrade);
   countingvalue++;
}
else if(countingvalue==numberofgrades)
{
    for(var j=1;j<numberofgrades;j++){
        averagetotal = grades[j]+averagetotal;
    }
}

    alert("Your average grade is: "+(averagetotal/numberofgrades));
}

</script>