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JavaScript | String startsWith() Method

The str.startsWith() method is used to check whether the given string start with the characters of the specified string or not.

Syntax:

str.startsWith( searchString , position )

Parameters: This method accepts two parameters as mentioned above and described below:

  • searchString: It is required parameter. It stores the string which needs to search.
  • start: It determines the position in the given string from where the searchString is to be searched. The default value is zero.

Return value This function returns the Boolean value true if the searchString is found else returns false.

Examples for the above function are provided below:



Example 1:

var str = 'It is a great day.';
var value = str.startsWith('It'); 
print(value);

Output:

true

In the above example, the function startsWith() checks whether the string str starts with It or not. Since the string starts with It therefore it returns true.

Example 2:

var str = 'It is a great day.';
var value = str.startsWith('great');
print(value);

Output:

false

In this example, the function startsWith() checks whether the string str starts with great or not. Since great appears in the middle and not in the beginning of the string therefore it returns false.

Example 3:

var str = 'It is a great day.'
var value = str.startsWith('great',8);
print(value);

Output:

true

In this example the function startsWith() checks whether the string str starts with great or not at the specified index 8. Since great appears at the given index in the string therefore it returns true.

Below programs illustrate the startsWith() method in JavaScript:



Program 1:

<script>
// JavaScript to illustrate startsWith() function
  
function func() {
       
    // Original string
    var str = 'It is a great day.';
      
    // Checking the condition
    var value = str.startsWith('It'); 
    document.write(value);
}
func();
</script>

Output:

true

Program 2:

<script>
  
// JavaScript to illustrate 
// startsWith() function
function func() {
      
    // Original string
    var str = 'It is a great day.';
    var value = str.startsWith('great');
    document.write(value);
}
func();
</script>

Output:

false

Program 3:

<script>
  
// JavaScript to illustrate
// startsWith() function
function func() {
       
    // Original string
    var str = 'It is a great day.';
    var value = str.startsWith('great', 8);
    document.write(value);
}
  
// Function call
func();
  
</script>

Output:

true


This article is attributed to GeeksforGeeks.org

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