Javascript cheatsheet

Javascript function example
[code language=”javascript”]
var isEven = function(number) {
if(number%2===0)
return true;
else
return false;
};
console.log(isEven(9));
[/code]

Javascript for loop example
[code language=”javascript”]
for (var counter = 1; counter < 11; counter++) {
console.log(counter);
}
[/code]

Javascript while loop example
[code language=”javascript”]
var loop = function(){
var i=0;
while(i<3){
console.log("I’m looping!");
i++;
}
};

loop();
[/code]

Javascript switch example
[code language=”javascript”]
var answer = prompt("Enter a letter here!");

switch(answer) {
case ‘a’:
console.log("a");
break;
case ‘b’:
console.log("b");
break;
default:
console.log("not a, not b, some other letter");
break;
}
[/code]

Javascript array example
[code language=”javascript”]
var languages=["php","java","python","javascript","c++"];
for(var i=0; i<languages.length; i++)
{
console.log(languages[i]);
}
[/code]

Javascript object examples
[code language=”javascript”]
var BMW = {
cost:"too much",
speed:220,
country:"Germany"
}

var Ford = new Object();
Ford.cost = "OK";
Ford.speed = "210";
Ford.country = "USA";
[/code]

Javascript object with function in it
[code language=”javascript”]
var bob = new Object();
bob.age = 30;
bob.setAge = function (newAge){
bob.age = newAge;
};

bob.getYearOfBirth = function () {
return 2013 – bob.age;
};
console.log(bob.getYearOfBirth());
[/code]

Javascript class object example
[code language=”javascript”]
function StudentReport() {
var grade1 = 4;
var grade2 = 2;
var grade3 = 1;
this.getGPA = function() {
return (grade1 + grade2 + grade3) / 3;
};
}

var myStudentReport = new StudentReport();

for(var x in myStudentReport) {
if(typeof myStudentReport[x] !== "function") {
console.log("Muahaha! " + myStudentReport[x]);
}
}
console.log("Your overall GPA is " + myStudentReport.getGPA());
[/code]

Javascript Cash Register example
[code language=”javascript”]
function StaffMember(name,discountPercent){
this.name = name;
this.discountPercent = discountPercent;
}

var sally = new StaffMember("Sally",5);
var bob = new StaffMember("Bob",10);

// Create yourself again as ‘me’ with a staff discount of 20%
var me = new StaffMember("Peng",20);

var cashRegister = {
total:0,
lastTransactionAmount: 0,
add: function(itemCost){
this.total += (itemCost || 0);
this.lastTransactionAmount = itemCost;
},
scan: function(item,quantity){
switch (item){
case "eggs": this.add(0.98 * quantity); break;
case "milk": this.add(1.23 * quantity); break;
case "magazine": this.add(4.99 * quantity); break;
case "chocolate": this.add(0.45 * quantity); break;
}
return true;
},
voidLastTransaction : function(){
this.total -= this.lastTransactionAmount;
this.lastTransactionAmount = 0;
},
// Create a new method applyStaffDiscount here
applyStaffDiscount: function(employee){
this.total = this.total * (1-employee.discountPercent/100);
}

};

cashRegister.scan(‘eggs’,1);
cashRegister.scan(‘milk’,1);
cashRegister.scan(‘magazine’,3);
// Apply your staff discount by passing the ‘me’ object
// to applyStaffDiscount
cashRegister.applyStaffDiscount(me);

// Show the total bill
console.log(‘Your bill is ‘+cashRegister.total.toFixed(2));
[/code]