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Java Script

It is a scripting language that is used to make interactive web pages.

Java Script in HTML Document

You can insert javascript code using Script element We mostly use src for passing URL

Inserting JavaScript in Web page

HEAD BODY External File

It is Case Sensitive Language

Comments Single Line : // Multi Line : /* ...... */

Array var stu = ["name", "rollno", "branch"]

Object var stu = { name: "Neha", rollno: 67,branch: "DevOps" }

Control Flow Statement These are same as in C and C++ if if else switch while do...while for break continue

Attribute
When inputing using input then use placeholder for the message in a dialoge box.
mouseover and mouseout Form Validation : required inside input block or username.value.trim() it will erase all spaces

PopUp Box

alert

<!DOCTYPE HTML>
<!DOCTYPE html>
<html>
<head>
	<title>Using Alert</title>
</head>
<body>

<script type="text/javascript">

	alert("Welcome!");
</script>

</body>
</html>

confirm

<!DOCTYPE html>
<html>
<head>
	<title>Using Confirm Box</title>
</head>
<body>

<script type="text/javascript"> 
	var choice = confirm("Do you really want to leave all your friends?");
	if(choice)
		document.write("Ignore all People!");
	else
		document.write("Dont do this to yourself");
</script>

</body>
</html>

Prompt

<!DOCTYPE html>
<html>
<head>
	<title>Using prompt</title>
</head>
<body>

<button onclick="myFunction()">Check Result</button>

<p id="demo"></p>

<script type="text/javascript">
	var name = prompt("Enter your name", "Pranjal");
	if(name==null || name==" ") name = "visitor";
	{
		document.write("Hi "+ name + " Welcome!<br><br>")
	}
}
</script>

</body>
</html>

Functions

With parameters
Without Parameter

Built In Global Functions

alert
prompt
confirm
eval
isFinite
isNaN
parseInt
parseFloat
Number
escape
unescape

<!DOCTYPE html>
<html>
<head>
	<title>Using prompt</title>
</head>
<body>

<button onclick="myFunction()">Check Result</button>

<p id="demo"></p>

<script type="text/javascript">
	var name = prompt("Enter your name", "Pranjal");
	if(name==null || name==" ") name = "visitor";
	{
		document.write("Hi "+ name + " Welcome!<br><br>")
	}

	var number = prompt("Enter your number", "9587760834");
	if(name==null || name==" ") name = "9587760834";
	{
		document.write("Your number is "+ number + "<br><br>" );
	}

	var iffinite = isFinite(number);
	document.write("Your number is "+ number +", is it finite?"+ iffinite + "<br><br>");

	var tofloat = parseFloat(number);
	document.write("Your number in float is " + tofloat + "<br><br>");

	var toint = parseInt(number);
	document.write("Your number in integer is "+ toint + "<br><br>");

	var num1 = "5873945";
	document.write("The number given in string is in integer now!! "+ num1 +"<br><br>");

	function myFunction() {
	var x = 10;
	var y = 20;
	var a = eval("x * y") + "<br>";

	var res = a;
	document.write("Result is " + a);
}

</script>

</body>
</html>

Events

Showing events of HTML form (within, mouse)

Showing the keyword events

Showing the events for media element

Showing the event of browser

Objects

BuiltIn objects String

1.
<!DOCTYPE html>
<html>
<head>
	<title>edx1</title>
</head>
<script type="text/javascript">
	var i=0;
	document.write(i);
</script>
<body>

</body>
</html>

2.

RegExp
Boolean
Number
Array
Math
Date

Working with browser objects

Browser Objects
Created by browser at the time of loading a Web Page.

Window Object

Used to open Window to display Web Page.

Window Obeject Properties
window.propertyName

Fetching API / AJAX(XHR)