Javascript
Methods & Events
By : Omar Hussein Mohamed

toString() (Array Method)
 The toString() method any type of data as a string .
 The toString() method doesn’t change the original string .
 The toString() can be used to convert a string object into a string .
let text = "Hello World!";
let result = text;
// result = Hello World! //

join() (Array Method)
 The join() method returns an array as a string .
 The join() method doesn’t change in the original array .
 Any separator can be specified. The default is comma (,).
const fruits = [“banana” , “Orange” , “Apple” , “Mango”];
let result = fruits.join();
// result = Banana,Orange,Apple,Mango//

contact() (Array Method)
 The concat() method joins two or more arrays.
 The concat() method returns a new array, containing the joined arrays.
 The concat() method does not change the existing arrays.
const arr1 = [“Javascript” , “C++” , “PHP”];
const arr2 = [“Python” , “Kotlin” , “html”];
let result = arr1.concat(arr2)
// result = Javascript,C++,PHP,Python,Kotlin,html//

some() (Array Method)
 The some() method checks if any of the elements in an array pass a test.
 The some() method does not change the original array.
 The some() method returns true (and stops) if the function returns true for one of the array
elements.
 The some() method returns false if the function returns false for all of the array elements.
const age = [3, 10 , 18 , 20];
function check(age) {
return age > 18;
}
let result = age.some(check);
// result = true //

every() (Array Method)
 every() returns true if all elements in an array pass a test (provided as a function).
 every() method returns true if the function returns true for all elements.
 every() method returns false if the function returns false for one element.
 every() method does not change the original array.
const age = [32, 33 , 16 , 40];
function check(age) {
return age > 18;
}
let result = age.every(check);
// result = false //

indexOf() (Array Method)
 The indexOf() method returns the first index (position) of a specified value.
 The indexOf() method returns -1 if the value is not found.
 The indexOf() method starts at a specified index and searches from left to right.
const code = [“html” , “javascript” , “python” , “php”];
let result = code.indexOf(“javascript”);
// result = 1 //

onmouseover (Event)
 The onmouseover event occurs when the mouse pointer enters an
element.
 The onmouseover event is often used together with the onmouseout
event, which occurs when the mouse pointer leaves the element.

onmouseout (Event)
 The onmouseout event occurs when the mouse pointer moves out of an
element.
 The onmouseout event is often used together with the onmouseover event,
which occurs when the pointer is moved over an element

onmousedown (Event)
 The onmousedown event occurs when a user presses a mouse button over an HTML element.
const text = document.createElement(‘p’);
Text.innerHTML = “Hello World”
Text.addEventListener(“mousedown” , ()=>{
text.style.color = “red”
})
//note : in addEventListener method we use only “mousedown”//

onmouseup (Event)
 The onmouseup event occurs when a mouse button is released over an element.
const text = document.createElement(‘p’);
Text.innerHTML = “Hello World”
Text.addEventListener(“mouseup” , ()=>{
text.style.color = “blue”
})
//note : in addEventListener method we use only “mouseup”//

Best Regards