Simple Javascript Student Grading (Free Download)

Welcome to a tutorial on how to create a simple student grading page in Javascript. Creating your own grading system, or got one of these as a boring assignment? Well, a student grading page isn’t too difficult to deal with. Read on!

 

 

TABLE OF CONTENTS

 

 

STUDENT GRADING DEMO

Enter 1-100 for each subject, then hit “calculate”.

 

 

PART 1) THE HTML

 <!-- (A) ENTER MARKS -->
<form id="gradeForm"></form>
 
<!-- (B) CALCULATIONS -->
<div id="gradeCalc">
  <div class="row">
    <div class="grade">Total</div>
    <div id="gradeT"></div>
  </div>
  <div class="row">
    <div class="grade">Average</div>
    <div id="gradeA"></div>
  </div>
</div>

The HTML should be pretty straightforward.

1. An HTML form to input the points for each subject. We will use Javascript to generate the form fields.
2. The total and average points.

 

PART 2) THE JAVASCRIPT

2A) PROPERTIES

var gradr = {
  // (A) PROPERTIES
  subjects : ["English", "Math", "Science", "Arts"],
  min : 0, max: 100,
  // ...
};

Once again, the first part of the Javascript is self-explanatory. These are the subjects, and the min/max points.

 

 

2B) INIT

// (B) INIT
init : () => {
  // (B1) HTML FORM
  let form = document.getElementById("gradeForm");
  form.onsubmit = () => gradr.calc();
 
  // (B2) CREATE FORM FIELDS
  let element;
  for (let s of gradr.subjects) {
    // (B2-1) SUBJECT LABEL
    element = document.createElement("label");
    element.innerHTML = s;
    form.appendChild(element);
 
    // (B2-2) SUBJECT MARKS INPUT
    element = document.createElement("div");
    element.name = s;
    element.className = "row";
    element.innerHTML = `<div class="grade"></div><input type="number" min="${gradr.min}" max="${gradr.max}" required>`;
    form.appendChild(element);
  }
 
  // (B2-3) SUBMIT BUTTON
  element = document.createElement("input");
  element.type = "submit";
  element.value = "Calculate";
  form.appendChild(element);
},
 
// ...
 
window.onload = gradr.init;

On window load, gradr.init() will run. Not going to explain line-by-line, but what it essentially does is loop through gradr.subjects and create the HTML form fields.

 

 

2C) CALCULATION

// (C) CALCULATE GRADES
calc : () => {
  // (C1) VARIABLES
  let marks, grade, average = 0, total = 0,
      subjects = document.querySelectorAll("#gradeForm input[type=number]");

  // (C2) LOOP THROUGH SUBJECTS
  for (let s of subjects) {
    // (C2-1) ADD TO TOTAL
    marks = parseInt(s.value);
    total += marks;

    // (C2-2) GRADE
    if (marks>=70) { grade = "A"; }
    else if (marks>=60) { grade = "B"; }
    else if (marks>=50) { grade = "C"; }
    else if (marks>=40) { grade = "D"; }
    else if (marks>=30) { grade = "E"; }
    else { grade = "F"; }
    s.previousSibling.innerHTML = grade;
  }

  // (C3) TOTAL & AVERAGE
  document.getElementById("gradeT").innerHTML = total;
  document.getElementById("gradeA").innerHTML = (total / subjects.length).toFixed(2);

  // (C4) PREVENT FORM SUBMIT
  return false;
}

On form submit, gradr.calc() will run. No need to panic. All this does is get all the <input> fields, calculate the totals, and update the HTML. The end.

 

 

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EXAMPLE CODE DOWNLOAD

Click here for the source code on GitHub gist, just click on “download zip” or do a git clone. I have released it under the MIT license, so feel free to build on top of it or use it in your own project.

 

 

COMPATIBILITY CHECKS

• Arrow Functions – CanIUse

This example will work on most browsers.

 

LINKS & REFERENCES

• Example on CodePen – Javascript Student Grades