Description

The JavaScript String method startsWith() checks if a string starts with a specific text.

  • The method returns true if the string starts with a given text, otherwise returns false.
  • The method is case-sensitive.

Syntax

The method startsWith() has the below syntax, where str is a string.

str.startsWith(searchString, startIndex)

Parameters

The method startsWith() allows the below parameters.

searchString

  • It is a character(s) to be searched for at the beginning of the string str.

startIndex (optional)

  • It defines the beginning index to start searching for the string searchString.
  • The default value is 0, which means from the beginning of the string str.

Result

Returns true if the string str starts with searchString. Otherwise returns false.

Example 1: Using the Method

The below example shows the basic usage of the method.

var str = "Learning JavaScript is fun";

// Returns true
document.write(str.startsWith(""));                      // Prints: true
document.write(str.startsWith("Learn"));                 // Prints: true
document.write(str.startsWith("Learning"));              // Prints: true
document.write(str.startsWith("Learning JavaScript"));   // Prints: true

// Returns false
document.write(str.startsWith("JavaScript"));   // Prints: false
document.write(str.startsWith("fun"));          // Prints: false
document.write(str.startsWith("hello"));        // Prints: false

Output:

true
true
true
true
false
false
false

Example 2: Method is Case-Sensitive

The method is case-sensitive, so it returns true only if both the text and its case are matched.

var str = "Learning JavaScript is fun";

// Case matching
document.write(str.startsWith("Learning"));    // Prints: true

// Case not matching
document.write(str.startsWith("learning"));    // Prints: false

Output:

true
false

Example 3: Using the Method with Position

If we need to check if a string contains a specific text at a specific index, we can use the position parameter.

var str = "Learning JavaScript is fun";

// Case matching
document.write(str.startsWith("Learning", 9));    // Prints: false

// Case not matching
document.write(str.startsWith("JavaScript", 9));  // Prints: true

Output:

false
true

Overall

The JavaScript String method startsWith() checks if a string starts with a specific text.

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