JavaScript String toLowerCase() Method

The JavaScript String toLowerCase() method converts all the characters in a string to lowercase letters. It does not change the original string, but returns a new string.

Syntax

Following is the syntax of JavaScript String toLowerCase() method −

toLowerCase()

Parameters

It does not accept any parameters.

Return value

This method returns a string with all characters in lowercase.

Example 1

The following example demonstrates the to usage this method. It converts the characters of the string "TUTORIALSPOINT" into lowercase letters.

<html>
<head>
<title>JavaScript String toLowerCase() Method</title>
</head>
<body>
<script>
   const original_str = "TUTORIALSPOINT";
   document.write("Original string is: ", original_str);
   const lowercase_str = original_str.toLowerCase();
   document.write("<br>New string(after converting into lowercase) is: ", lowercase_str);
</script>
</body>
</html>

Output

The above program returns "tutorialspoint" in the output −

Original string is: TUTORIALSPOINT
New string(after converting into lowercase) is: tutorialspoint

Example 2

Let's compare two strings after converting one of them "HELLOWORLD" to lowercase letters and display a statement based on the criteria satisfied.

<html>
<head>
<title>JavaScript String toLowerCase() Method</title>
</head>
<body>
<script>
   const str1 = "helloworld";
   const str2 = "HELLOWORLD";
   document.write("str1 = ", str1);
   document.write("<br>str2 = ", str2);
   document.write("<br>Before conversion:<br>");
   if(str1 === str2){
      document.write("String str1 and str2 are equal");
   }
   else{
      document.write("String str1 and str2 are not equal");
   }
   document.write("<br>After conversion:<br>");
   if(str1 === str2.toLowerCase()){
      document.write("String str1 and str2 are equal");
   }
   else{
      document.write("String str1 and str2 are not equal");
   }
</script>
</body>
</html>

Output

After executing the above program, it displays the following statements as −

str1 = helloworld
str2 = HELLOWORLD
Before conversion:
String str1 and str2 are not equal
After conversion:
String str1 and str2 are equal

Example 3

Let's use the charAt() and toLowerCase() methods to convert a specific character in a string to lowercase. In this example, we retrieve a specific character in the string using the charAt() method and try to convert it to lowercase using the toLowerCase() method.

<html>
<head>
<title>JavaScript String toLowerCase() Method</title>
</head>
<body>
<script>
   const str = "TutorialsPoint";
   document.write("String str = ", str);
   document.write("<br>After converting a specific character '", str.charAt(9), "' into in lowercase: ");
   document.write(str.charAt(9).toLowerCase());
</script>
</body>
</html>

Output

The above program converts a specific character 'P' to a lowercase.

String str = TutorialsPoint
After converting a specific character 'P' into in lowercase: p

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