The code below is an HTML document with embedded JavaScript code. Let’s go through the code step by step to understand its structure and functionality.
- HTML Structure:
<!DOCTYPE html>
: This declaration specifies that the document type is HTML.<html>
: The<html>
element is the root element of an HTML page.<head>
: The<head>
element contains meta-information about the document, such as the title and included stylesheets or scripts.<meta>
: The<meta>
element specifies the character encoding for the document.<title>
: The<title>
element sets the title of the HTML page, which appears in the browser’s title bar or tab.<style>
: The<style>
element is used to define CSS styles for the document.<body>
: The<body>
element contains the visible content of the HTML page.
- CSS Styles:
.btn
: This class selector defines the styling for elements with the class name “btn.” In this case, it sets padding, border, display, and margin properties..oput
: This class selector defines the styling for elements with the class name “oput.” It sets padding, margin, font size, and color properties.
- HTML Content:
<div id="main">
: This<div>
element has an id attribute set to “main” and serves as the main container for the page.- Inputs: Two
<input>
elements with the names “numA” and “numB” are present. They have initial values of 6 and 33, respectively. - Buttons: Two
<div>
elements with ids “btn1” and “btn2” serve as buttons. They have the “btn” class applied to them. - Output Div: A
<div>
element with the “output1” id is used to display the output of the JavaScript code. It initially contains the text “nothing.” Another<div>
element with the “output2” id is also present but not used in the JavaScript code.
- JavaScript Code:
<script>
: The<script>
element is used to embed or reference JavaScript code within an HTML document.const
andlet
Declarations: Four variables are declared using theconst
andlet
keywords:btn1Click
,btn2Click
,output1
, andoutput2
. These variables are assigned references to specific elements in the HTML document using thegetElementById
method.- Event Handler Registration: The
onclick
event handlers are registered forbtn1Click
using themyFun
function. It means that whenbtn1Click
is clicked, themyFun
function will be executed. myFun
Function: This function is defined to handle the click event ofbtn1Click
.- It retrieves the value of the input element with the id “numA” using
document.getElementById("numA").value
and assigns it to the variablea
. - A variable
myContainer
is initialized as an empty string. - The value of
a
is then checked using aswitch
statement. - Inside the
switch
statement, different cases are defined based on the value ofa
. - If
a
is “0”, “2”, or “7”, the corresponding case is executed, and the value ofmyContainer
is set accordingly. - If none of the cases match, the
default
case is executed, and the value ofmyContainer
is set to “NOTHING HERE”. - The value of
myContainer
is then assigned to thetextContent
property ofoutput1
, which updates the text displayed in the corresponding<div>
.
- It retrieves the value of the input element with the id “numA” using
<!DOCTYPE html>
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
<title>Case_Switch Statement</title>
<style>
.btn {
padding: 5px;
border: 1px solid black;
display: inline-block;
margin: 5px;
}
.oput {
padding: 10px;
margin: 10px;
font-size: 18px;
color: blue;
}
</style>
</head>
<body>
<div id="main">
A
<input type"number" name="numA" id="numA" value="6" />
<br />B
<input type"number" name="numB" id="numB" value="33" />
<div>
<div id="btn1" class="btn">Button 1</div>
<br />
<div id="btn2" class="btn">Button 2</div>
</div> <!--Button Div -->
<div>Output:
<div id="output1" class="oput">nothing</div>
<div id="output2" class="oput">nothing</div>
</div><!--Output Div -->
</div> <!--Main Div -->
<script>
const btn1Click = document.getElementById("btn1");
const btn2Click = document.getElementById("btn2");
const output1 = document.getElementById("output1");
const output2 = document.getElementById("output2");
btn1Click.onclick = myFun;
function myFun() {
const a = document.getElementById("numA").value;
let myContainer = "";
console.log(a);
switch (a) {
case "0":
myContainer = "ZERO";
break
case "2":
myContainer = "TWO";
break
case "7":
myContainer = "SEVEN";
break
default:
myContainer = "NOTHING HERE";
}//End Switch statement
output1.textContent = myContainer;
} // end function myFun
</script>
</body>
</html>