index.js

// // Prompt user to enter student's marks
// let marks = prompt("Please enter the student's marks (between 0 and 100):");
// // Convert marks to a number
// marks = Number(marks);

// // Check if marks are within the valid range
// if (marks < 0 || marks > 100) {
//   console.log(window.alert("Invalid marks entered. Please enter a value between 0 and 100."));
// } else {
//   // Assign grade based on marks
//   let grade;
//   if (marks > 79) {
//     grade =window.alert('Your grade is A');
//   } else if (marks >= 60 && marks <= 79) {
//     grade = window.alert('Your grade is B');
//   } else if (marks >= 50 && marks <= 59) {
//     grade = window.alert('Your grade is C');
//   } else if (marks >= 40 && marks <= 49) {
//     grade = window.alert('Your grade is D');
//   } else {
//     grade = window.alert('Your grade is E');
//   }

//   // Output the grade
//   console.log(`The student's grade is ${grade}.`);
// }