jQuery - phonebook

http://stackoverflow.com/questions/33206183/how-to-delete-element-from-list-in-jquery

HTML

<div id="container">
    <label>Name</label>
    <input type="text" id="nameEdit">
    <label>Number</label>
    <input type="number" id="numberEdit">
    <button id="addItem">Add</button>
    <ul id="phonelist"></ul>
</div>

JavaScript

function Phonebook() {
    this.phoneBookArray = [];
    var defaultvalue = [{
        name: "abc",
        phonenumber: 989123
    }, {
        name: "pqr",
        phonenumber: 9891462
    }]
    this.phoneBookArray = defaultvalue;
    console.log(this.phoneBookArray)
}
Phonebook.prototype.addItem = function (username, phoneNumber) {
    this.phoneBookArray.push({
        name: username,
        phonenumber: phoneNumber
    })
    this.displayItem();
}

Phonebook.prototype.displayItem = function () {
    $("#phonelist").html('');
    for (var i = 0; i < this.phoneBookArray.length; i++) {
        $("#phonelist").append('<li><span>' + this.phoneBookArray[i].name + '</span><span>' + this.phoneBookArray[i].phonenumber + '</span><span><button class="del" data-phone=' + this.phoneBookArray[i].phonenumber + '>delete</button></span><span><button class="update" data-phone=' + this.phoneBookArray[i].phonenumber + '>update</button></span></li>')
    }
}

Phonebook.prototype.deleteItem = function (index) {
    this.phoneBookArray.splice(index, 1);
    this.displayItem();
}

Phonebook.prototype.updateItem = function (index, data) {
    this.phoneBookArray[index] = {
        name: data[0],
        phonenumber: data[1]
    };
    this.displayItem();
}

Phonebook.prototype.findIndex = function (phone) {
    var index;
    for (var i = 0, length = this.phoneBookArray.length; i < length; i++) {
        if (this.phoneBookArray[i].phonenumber == phone) {
            index = i;
            break;
        }
    }

    return index;
}

var phonedir = new Phonebook();
phonedir.displayItem();
$('#addItem').click(function () {

    var name = $('#nameEdit').val();
    var phone = $('#numberEdit').val();

    if (name != '' && phone != "") {
        phonedir.addItem(name, phone);
        $('#nameEdit').val('');
        $('#numberEdit').val('');
    } else {
        alert('please enter number and name')
    }

})


$(document).on('click', '.del', function () {
    var phone =...