JS Tutorial
JS Version
JS Objects
JS Function
JS Classes
JS Async
JS HTML DOM
JS Browser BOM
JS Web API
JS AJAX
JS JSON
JS vs JQUERY
JS Graphics
JavaScript String Search
JavaScript String indexOf()
The indexOf() method returns the index of (the position of) the first occurrence of a specified text in a string:
Example
<!DOCTYPE html>
<html>
<body>
<h2>JavaScript String Methods</h2>
<p>The indexOf() method returns the position of the first occurrence of a specified text:</p>
<p id=”demo”></p>
<script>
let str = “Please locate where ‘locate’ occurs!”;
document.getElementById(“demo”).innerHTML = str.indexOf(“locate”);
</script>
</body>
</html>
Output
JavaScript String Methods
The indexOf() method returns the position of the first occurrence of a specified text:
7
JavaScript String lastIndexOf()
The lastIndexOf() method returns the index of the last occurrence of a specified text in a string:
<!DOCTYPE html>
<html>
<body>
<h2>JavaScript String Methods</h2>
<p>The lastIndexOf() method returns the position of the last occurrence of a specified text:</p>
<p id=”demo”></p>
<script>
let str = “Please locate where ‘locate’ occurs!”;
document.getElementById(“demo”).innerHTML = str.lastIndexOf(“locate”);
</script>
</body>
</html>
Output
JavaScript String Methods
The lastIndexOf() method returns the position of the last occurrence of a specified text:
21
Both indexOf(), and lastIndexOf() return -1 if the text is not found:
Example
<!DOCTYPE html>
<html>
<body>
<h2>JavaScript String Methods</h2>
<p>Both indexOf(), and lastIndexOf() return -1 if the text is not found:</p>
<p id=”demo”></p>
<script>
let str = “Please locate where ‘locate’ occurs!”;
document.getElementById(“demo”).innerHTML = str.indexOf(“John”);
</script>
</body>
</html>
Output
Both indexOf(), and lastIndexOf() return -1 if the text is not found:
-1
Both methods accept a second parameter as the starting position for the search:
Example
<!DOCTYPE html>
<html>
<body>
<h2>JavaScript String Methods</h2>
<p>The indexOf() method accepts a second parameter as the starting position for the search:</p>
<p id=”demo”></p>
<script>
let str = “Please locate where ‘locate’ occurs!”;
document.getElementById(“demo”).innerHTML = str.indexOf(“locate”,15);
</script>
</body>
</html>
Output
JavaScript String Methods
The indexOf() method accepts a second parameter as the starting position for the search:
21
The lastIndexOf() methods searches backwards (from the end to the beginning), meaning: if the second parameter is 15, the search starts at position 15, and searches to the beginning of the string.
Example
<!DOCTYPE html>
<html>
<body>
<h2>JavaScript String Methods</h2>
<p>The lastIndexOf() method accepts a second parameter as the starting position for the search.</p>
<p>Remember that the lastIndexOf() method searches backwards, so position 15 means start the search at position 15, and search to the beginning.</p>
<p>Position 15 is position 15 from the beginning.</p>
<p id=”demo”></p>
<script>
let str = “Please locate where ‘locate’ occurs!”;
document.getElementById(“demo”).innerHTML = str.lastIndexOf(“locate”, 15);
</script>
</body>
</html>
Output
JavaScript String Methods
The lastIndexOf() method accepts a second parameter as the starting position for the search.
Remember that the lastIndexOf() method searches backwards, so position 15 means start the search at position 15, and search to the beginning.
Position 15 is position 15 from the beginning.
7
JavaScript String search()
The search() method searches a string for a specified value and returns the position of the match:
Example
<!DOCTYPE html>
<html>
<body>
<h2>JavaScript String Methods</h2>
<p>The search() method returns the position of the first occurrence of a specified text in a string:</p>
<p id=”demo”></p>
<script>
let str = “Please locate where ‘locate’ occurs!”;
document.getElementById(“demo”).innerHTML = str.search(“locate”);
</script>
</body>
</html>
Output
JavaScript String Methods
The search() method returns the position of the first occurrence of a specified text in a string:
7
JavaScript String match()
The match() method searches a string for a match against a regular expression, and returns the matches, as an Array object.
Example 1
Search a string for “ain”:
<!DOCTYPE html>
<html>
<body>
<h2>JavaScript String Search</h2>
<p>Search a string for “ain”:</p>
<p id=”demo”></p>
<script>
let text = “The rain in SPAIN stays mainly in the plain”;
document.getElementById(“demo”).innerHTML = text.match(/ain/g);
</script>
</body>
</html>
Output
JavaScript String Search
Search a string for "ain":
ain,ain,ain
Syntax:
string.match(regexp)
regexp Required. The value to search for, as a regular expression.
Returns: An Array, containing the matches, one item for each match, or null if no match is found
Example 2
Perform a global, case-insensitive search for “ain”:
<!DOCTYPE html>
<html>
<body>
<h2>JavaScript String Search</h2>
<p>Perform a global, case-insensitive search for “ain”:</p>
<p id=”demo”></p>
<script>
let text = “The rain in SPAIN stays mainly in the plain”;
document.getElementById(“demo”).innerHTML = text.match(/ain/gi);
</script>
</body>
</html>
Output
JavaScript String Search
Perform a global, case-insensitive search for "ain":
ain,AIN,ain,ain
JavaScript String includes()
The includes() method returns true if a string contains a specified value.
Example
<!DOCTYPE html>
<html>
<body>
<h2>JavaScript String Search</h2>
<p>Check if a string includes “world”:</p>
<p id=”demo”></p>
<p>The includes() method is not supported in Internet Explorer.</p>
<script>
let text = “Hello world, welcome to the universe.”;
document.getElementById(“demo”).innerHTML = text.includes(“world”);
</script>
</body>
</html>
Output
JavaScript String Search
Check if a string includes "world":
true
The includes() method is not supported in Internet Explorer.
Syntax
string.includes(searchvalue, start)
searchvalue Required. The string to search for
start Optional. Default 0. Position to start the search
Returns: Returns true if the string contains the value, otherwise false
JS Version: ES6 (2015)
Check if a string includes “world”, starting the search at position 12:
Example
<!DOCTYPE html>
<html>
<body>
<h2>JavaScript String Search</h2>
<p>Check if a string includes “world”:</p>
<p id=”demo”></p>
<p>The includes() method is not supported in Internet Explorer.</p>
<script>
let text = “Hello world, welcome to the universe.”;
document.getElementById(“demo”).innerHTML = text.includes(“world”, 12);
</script>
</body>
</html>
Output
JavaScript String Search
Check if a string includes "world":
false
The includes() method is not supported in Internet Explorer.
JavaScript String startsWith()
The startsWith() method returns true if a string begins with a specified value, otherwise false:
Example
<!DOCTYPE html>
<html>
<body>
<h2>JavaScript Strings</h2>
<p>Check if a string starts with “Hello”:</p>
<p id=”demo”></p>
<p>The startsWith() method is not supported in Internet Explorer.</p>
<script>
let text = “Hello world, welcome to the universe.”;
document.getElementById(“demo”).innerHTML = text.startsWith(“Hello”);
</script>
</body>
</html>
Output
JavaScript Strings
Check if a string starts with "Hello":
true
The startsWith() method is not supported in Internet Explorer.
Syntax
string.startsWith(searchvalue, start)
Example
<!DOCTYPE html>
<html>
<body
<h2>JavaScript Strings</h2>
<p>The startsWith() method.</p>
<p id=”demo”></p>
<p>The startsWith() method is not supported in Internet Explorer.</p>
<script>
let text = “Hello world, welcome to the universe.”;
document.getElementById(“demo”).innerHTML = text.startsWith(“world”, 6);
</script>
</body>
</html>
Output
JavaScript Strings
The startsWith() method.
true
The startsWith() method is not supported in Internet Explorer.
JavaScript String endsWith()
The endsWith() method returns true if a string ends with a specified value, otherwise false:
Example
Check if a string ends with “Doe”:
<!DOCTYPE html>
<html>
<body>
<h2>JavaScript Strings</h2>
<p>Check in the 11 first characters of a string ends with “world”:</p>
<p id=”demo”></p>
<p>The endsWith() method is not supported in Internet Explorer.</p>
<script>
let text = “Hello world, welcome to the universe.”;
document.getElementById(“demo”).innerHTML = text.endsWith(“world”, 11);
</script>
</body>
</html>
Output
JavaScript Strings
Check in the 11 first characters of a string ends with "world":
true
The endsWith() method is not supported in Internet Explorer.