Practice exercises CHAPTER 6 299
- Modify the numberClick, plusClick, minusClick, clearEntry, and clear functions to define
these functions on the Calculator prototype.
The CalculatorLibrary.js should look like the following.
///
(function () {
this.calculatorNamespace = this.calculatorNamespace || {};
var ns = this.calculatorNamespace;function initialize() {
for (var i = 0; i < 10; i++) {
document.getElementById('btn' + i)
.addEventListener('click', numberClick, false);
}
txtInput = document.getElementById('txtInput');
txtResult = document.getElementById('txtResult');document.getElementById('btnPlus')
.addEventListener('click', plusClick, false);
document.getElementById('btnMinus')
.addEventListener('click', minusClick, false);
document.getElementById('btnClearEntry')
.addEventListener('click', clearEntry, false);
document.getElementById('btnClear')
.addEventListener('click', clear, false);
clear();
}ns.Calculator = (function () {function Calculator() {
}Calculator.prototype.numberClick = function () {
txtInput.value = txtInput.value == '0'?
this.innerText : txtInput.value + this.innerText;
};Calculator.prototype.plusClick = function () {
txtResult.value = Number(txtResult.value) + Number(txtInput.value);
clearEntry();
};Calculator.prototype.minusClick = function () {
txtResult.value = Number(txtResult.value) - Number(txtInput.value);
clearEntry();
};Calculator.prototype.clearEntry = function () {
txtInput.value = '0';
};Calculator.prototype.clear = function () {