Write a JavaScript program which accept a string as input and swap the case of each character.

For example: if you input 'The Quick Brown Fox' the output should be 'tHE qUICK bROWN fOX'.

Solution

<!DOCTYPE HTML>
<html>
	<head>
		<title>Swap the Case</title>
		<style type="text/css">
			.error_msg
			{
				color:#ff0000;
				font-style:italic;
			}
		</style>
		<script language="javascript">
			function swap_case()
			{
				var data=document.getElementById('user_txt').value;
				var output='';
				document.getElementById('error').innerHTML="";
				document.getElementById('result').innerHTML="";
				var i,j;
				if(data=="")
				{
					document.getElementById('error').innerHTML="Please Enter the text";
				}
				else
				{
					for(i=0; i<data.length; i++)
					{
						if(data.charCodeAt(i)>=65&&data.charCodeAt(i)<=90)
						{                
							output+=data.charAt(i).toLowerCase();
						}
						else if(data.charCodeAt(i)>=97&&data.charCodeAt(i)<=122)
						{
							output+=data.charAt(i).toUpperCase();
						}
						else		
						{
							output+=data.charAt(i);
						}
					}
					document.getElementById('result').innerHTML=output;
				}
			}
		</script>
	</head>
	<body>	
		<form name="frm" id="frm">	
			<div>
				<label for="user_txt">Enter the Text</label>
			</div>
			<div>
				<textarea name="user_txt" id="user_txt" rows="10" cols="30"></textarea>
				<span class="error_msg" id="error"></span>
			</div>
			<div>
				<input type="button" name="check_btn" id="check_btn" value="Swap the Case" onclick="swap_case()"/>
			</div>
			<div>
				<h3>Output</h3>
				<span id="result"></span>
			</div>
			
		</form>
	</body>
</html>

Output

Programming Examples

Write a JavaScript program which accept a string as input and swap the case of each character.