How to Delete, Edit array items from Javascript

Question

Hi, all, please take a look at this code and help me to complete this.

 

Thank you.

var _students = [];
function addStudent() {
var lblMsgInfo = document.getElementById("labelMessageInfo");
lblMsgInfo.innerHTML = "";
if (isFormValid()) {
var regnum = document.getElementById("textboxRegistrationNumber").value;
var newStudent = {
RegNum: regnum
};
_students.push(newStudent);
var ul = document.getElementById("listStudents");
var li = document.createElement("li");
li.appendChild(document.createTextNode(newStudent.RegNum ));
ul.appendChild(li);
//alert('Student added successfully to the list');
lblMsgInfo.innerHTML = "Student added successfully to the list";
}
}
function isFormValid() {
//Validate form
var lblMsg = document.getElementById("labelMessageError");
lblMsg.innerHTML = "";
var regnum = document.getElementById("textboxRegistrationNumber").value;
if (regnum.length == 0) {
lblMsg.innerHTML = "Registration number is required";
return false;
} else if (isRegnumalreadyExist(regnum)) {
lblMsg.innerHTML = "Registration number already exist";
return false;
}
return true;
}
function isRegnumalreadyExist(regNum) {
for (var i = 0; i < _students.length; i++) {
if (_students[i].RegNum == regNum)
return true;
}
return false;
}
// Clear Function
function resetform() {
document.getElementById("myform").reset();
}
//Delete Function
function DeleteRecord() {
}