Java Cheatsheet

<script type="text/javascript">  ...</script>
                    

<script src="filename.js"></script>
                    

setTimeout(function () {

}, 1000);
                    

function addNumbers(a, b) {
return a + b; ;
}
x = addNumbers(1, 2);
                    

document.getElementById("elementID").innerHTML = "Hello World!";
                    

console.log(a); 
                    

/* Multi line
comment */
// One line
                    

for (var i = 0; i < 10; i++) {
document.write(i + ": " + i*3 + "
");
}
                    

var i = 1;                      // initialize
while (i < 100) {               // enters the cycle if statement is true
i *= 2;                     // increment to avoid infinite loop
document.write(i + ", ");   // output
}
                    

var i = 1;                      // initialize
do {                            // enters cycle at least once
i *= 2;                     // increment to avoid infinite loop
document.write(i + ", ");   // output
} while (i < 100) 
                    

for (var i = 0; i < 10; i++) {
if (i == 5) { break; }          // stops and exits the cycle
document.write(i + ", ");       // last output number is 4
}
                    

for (var i = 0; i < 10; i++) {
if (i == 5) { continue; }       // skips the rest of the cycle
document.write(i + ", ");       // skips 5
}
                    

if ((age >= 14) && (age < 19)) {        // logical condition
status = "Eligible.";               // executed if condition is true
} else {                                // else block is optional
status = "Not eligible.";           // executed if condition is false
}
                    

switch (new Date().getDay()) {      // input is current day
case 6:                         // if (day == 6)
	text = "Saturday";          
	break;
case 0:                         // if (day == 0)
	text = "Sunday";
	break;
default:                        // else...
	text = "Whatever";
} 
                    

"use strict";   // Use strict mode to write secure code
x = 1; 
                    

false, true                     // boolean
18, 3.14, 0b10011, 0xF6, NaN    // number
"flower", 'John'                // string
undefined, null , Infinity      // special
                    

a = b + c - d;      // addition, substraction
a = b * (c / d);    // multiplication, division
x = 100 % 48;       // modulo. 100 / 48 remainder = 4
a++; b--;           // postfix increment and decrement
                    

try {                           // block of code to try
undefinedFunction();
}
catch(err) {                    // block to handle errors
console.log(err.message);
}
                    

throw "My error message";    // throw a text
                    

var x = document.getElementById("mynum").value; // get input value
try { 
if(x == "")  throw "empty";                 // error cases
if(isNaN(x)) throw "not a number";
x = Number(x);
if(x > 10)   throw "too high";
}
catch(err) {                                    // if there's an error
document.write("Input is " + err);          // output error
console.error(err);                         // write the error in console
}
finally {
document.write("
Done");              // executed regardless of the try / catch result
}