Javascript code snippets

alert.js

window.alert("Hello World!");

code.js

document.write("Hello World!");

code1.js

var a,b,c,d,e,f,g,h,i,j,k=21,l=25,m=35,n=36,o=37,p,q,r,s,t,u,v,w;
a = "I am javascript";
b = a;
c = 10;
d = 5;
e = 3;
f = c + d;
g = c - d;
h = c * e;
i = c / d;
j = c % e;
k += g;
l -= g;
m *= l;
n /= m;
o %= d;
p = c < d;
q = c > d;
r = c <= d;
s = c >= d;
t = c == d;
u = c != d;
v = !(c == d) && (s);
w = p || q;
document.write(
"Hello World!" + "<br>" +
b + "<br>" +
"f " + "= " + f + "<br>" +
"g " + "= " + g + "<br>" +
"h " + "= " + h + "<br>" +
"i " + "= " + i + "<br>" +
"j " + "= " + j + "<br>" +
"k " + "= " + k + "<br>" +
"l " + "= " + l + "<br>" +
"m " + "= " + m + "<br>" +
"n " + "= " + n + "<br>" +
"o " + "= " + o + "<br>" +
"p " + "= " + p + "<br>" +
"q " + "= " + q + "<br>" +
"r " + "= " + r + "<br>" +
"s " + "= " + s + "<br>" +
"t " + "= " + t + "<br>" +
"u " + "= " + u + "<br>" +
"v " + "= " + v + "<br>" +
"w " + "= " + w + "<br>" +
typeof parseFloat + "<br>" +
typeof a + "<br>" +
typeof x + "<br>" +
typeof c + "<br>" +
typeof v + "<br>" +
typeof window + "<br>" +
typeof document.write
);

conditionalOperator.js

var game = "watchDog";
message = (game=="watchDog") ? "I love UbiSoft! <br>" : "Fifa rocks! <br>";
document.write(message);

do_while.js

var x = 0;
do {
	document.write("i = " + x + "<br>");
	x++;
}
while (x<5);

do_while1.js

var x = 10;
do {
	document.write("i = " + x + "<br>");
	x++;
}
while (x<5);

do_while1_output

i = 10

do_while_loop

do {
	code to be executed
}
while (condition);

do_while_output

i = 0
i = 1
i = 2
i = 3
i = 4

for.js

for (i=0; i<5; i++) {
	document.write("i = " + i + "<br>");
}

for_in.js

var obj = {number:10, bool:true, string:"www.masteringcodes.com"};
for (var prop in obj) {
	document.write(prop + ' - ' + obj[prop] + '<br />');
}

for_in_loop

for (variable in object) {
	instructions
}

for_in_output

number - 10
bool - true
string - www.masteringcodes.com

for_loop

for (initialization; condition; increment) {
    code to be executed
}

for_output

i = 0
i = 1
i = 2
i = 3
i = 4

forEach.js

var arr = [10, 'www.masteringcodes.com', "https://www.masteringcodes.com"];

// callback function
function myArr(val, index) {
  document.write('['+ index + '] = ' + val +'<br/>');
}

arr.forEach(myArr);

forEach_output

[0] = 10
[1] = www.masteringcodes.com
[2] = https://www.masteringcodes.com

function.js

function multiply(a, b) {
	return a*b;
}

var x = multiply(5,15);
document.write(x);

function1.html

<form>
	<input type="button" onclick="msg('It\'s pizza time!')" value="Pizza" />
	<input type="button" onclick="msg('Let\'s play fifa!')" value="Fifa" />
</form>

function1.js

function msg(text) {
  alert(text);
}

function_structure

function functionName(parameter1, parameter2, ...) {
	code to be executed
}

function_variable.js

var va = 'variable';

function myF() {
	var va = 'function';
	document.write(va + '<br>');
}

// Calling the function
myF();

//Printing 'va'
document.write(va + '<br>');

function_variable1.js

var va = 'variable';

function myF() {
	va = 'function';
	document.write(va + '<br>');
}

// Calling the function
myF();

//Printing 'va'
document.write(va + '<br>');

functionFixedArguments.js

function addNumbers(a,b,c,d,e) {
	if (!a) a = 0;
	if (!b) b = 0;
	if (!c) c = 0;
	if (!d) d = 0;
	if (!e) e = 0;

	return a + b + c + d + e;
}

document.write("1 + 2 + 3 = " + addNumbers(1,2,3));

functionNested.js

function addAndSquare(a,b) {
	// Get the summation of 'a' and 'b'
	var sum = a+b;
	
	// Nested function
	function multiply(x) {
		return x*x;
	}
	
	return multiply(sum);
}

//first add 8 + 12 = 20, then sqrt(20) = 400
document.write( addAndSquare(8,12) );

functionRecursive.html

<form>
	<input type = "button" value = "Factorial 4" onclick="alert(factorial(4))" >
</form>

functionRecursive.js

function factorial(n) {
	var result;
	if (n>0) result = n*factorial(n-1);
	else if (n==0) result = 1;
	else result = null;
	return result;
}

functionUnlimitedArguments.js

function addNumbers() {
	
	// Sets a variable that will return the final result
	var sum = 0;
	
	// go through the arguments Array and adds every value to "sum" variable
	for(var i=0; i<addNumbers.arguments.length; i++) {
		sum += addNumbers.arguments[i];
	}

	return sum;
}

document.write("1 + 2 + 3 = " + addNumbers(1,2,3));

if_else.js

var game = "fifa";
if (game=="fifa")
	document.write("Fifa rocks! <br>");
else
	document.write("I love UbiSoft! <br>");

index.html

<html>
<head>
<title>Learn JavaScript</title>
</head>
<body>

<script type="text/javascript">
  document.write("Hello World!");
</script>

</body>
</html>

index1.html

<html>
<head>
<title>Learn JavaScript</title>
</head>
<body>

<script type="text/javascript" src="code.js"></script>

</body>
</html>

output1

Hello World!
I am javascript
f = 15
g = 5
h = 30
i = 2
j = 1
k = 26
l = 20
m = 700
n = 0.05142857142857143
o = 2
p = false
q = true
r = false
s = true
t = false
u = true
v = true
w = true
function
string
undefined
number
boolean
object
function

switch.js

var d = new Date();
var day = d.getDay();

switch(day) {
	case 0:
		document.write("Today is Sunday");
		break;
	case 1:
		document.write("Today is Monday");
		break;
	case 2:
		document.write("Today is Tuesday");
		break;
	case 3:
		document.write("Today is Wednesday");
		break;
	case 4:
		document.write("Today is Thursday");
		break;
	case 5:
		document.write("Today is Friday");
		break;
	default:
		document.write("Today is Saturday");
}

while.js

var i = 0;
while (i<5) {
	document.write("i = " + i + "<br>");
	i++;
}

while_loop

while (condition) {
	code to be executed
}

while_output

i = 0
i = 1
i = 2
i = 3
i = 4

window.confirm.js

var question = window.confirm("The result of 10+0 is 10?");
if
	(question) alert("Correct answer!");
else
	alert("Wrong answer!");

window.confirm_structure

window.confirm("Question");

window.prompt.js

var msg = window.prompt("Write your name", "First name Last name");
alert(msg);

window.prompt_structure

window.prompt("Message", DefaultValue);