JavaScript String Search
JavaScript Search Methods
- String indexOf()
- String lastIndexOf()
- String startsWith()
- String endsWith()
JavaScript String indexOf()
The indexOf() method returns the index of (the position of)
the first occurrence of a specified text in a string:
Note
JavaScript counts positions from zero.
0 is the first position in a string, 1 is the second, 2 is the third, ...
JavaScript String lastIndexOf()
The lastIndexOf() method returns the index of the last
occurrence of a specified text in a string:
Example
let str = "Please locate where 'locate' occurs!";
str.lastIndexOf("locate");
Try it Yourself »
Both indexOf(), and lastIndexOf() return -1
if the text is not found:
Example
let str = "Please locate where 'locate' occurs!";
str.lastIndexOf("John");
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Both methods accept a second parameter as the starting position for the search:
Example
let str = "Please locate where 'locate' occurs!";
str.indexOf("locate", 15);
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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
let str = "Please locate where 'locate' occurs!";
str.lastIndexOf("locate", 15);
Try it Yourself »
JavaScript String search()
The search() method searches a string for a specified value
and returns the position of the match:
Did You Notice?
The two methods, indexOf() and search(), are equal?
They accept the same arguments (parameters), and return the same value?
The two methods are NOT equal. These are the differences:
- The
search()method cannot take a second start position argument. - The
indexOf()method cannot take powerful search values (regular expressions).
You will learn more about regular expressions in a later chapter.
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":
let text = "The rain in SPAIN stays mainly in the plain";
text.match(/ain/g);
Try it Yourself »
Read more about regular expressions in the chapter JS RegExp.
Note
If a regular expression does not include the g modifier (to perform a global search), the match() method will return only the first match in the string.
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":
let text = "The rain in SPAIN stays mainly in the plain";
text.match(/ain/gi);
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JavaScript String includes()
The includes() method returns true if a string contains a specified value.
Example
let text = "Hello world, welcome to the universe.";
text.includes("world");
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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:
let text = "Hello world, welcome to the universe.";
text.includes("world", 12);
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Browser Support
includes() is an ES6 feature (JavaScript 2015).
It is supported in all modern browsers:
| Chrome | Edge | Firefox | Safari | Opera |
| Yes | Yes | Yes | Yes | Yes |
includes() 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
let text = "Hello world, welcome to the universe.";
text.startsWith("Hello");
Try it Yourself »
Syntax
string.startsWith(searchvalue, start)
Parameter Values
| Parameter | Description |
|---|---|
| searchvalue | Required. The value to search for. |
| start | Optional. Default 0. The position to start the search. |
Examples
let text = "Hello world, welcome to the universe.";
text.startsWith("world") // Returns false
let text = "Hello world, welcome to the universe.";
text.startsWith("world", 5) // Returns false
let text = "Hello world, welcome to the universe.";
text.startsWith("world", 6) // Returns true
Try it Yourself »
Note
The startsWith() method is case sensitive.
Browser Support
startsWith() is an ES6 feature (JavaScript 2015).
It is supported in all modern browsers:
| Chrome | Edge | Firefox | Safari | Opera |
| Yes | Yes | Yes | Yes | Yes |
startsWith() 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":
let text = "John Doe";
text.endsWith("Doe");
Try it Yourself »
Syntax
string.endsWith(searchvalue, length)
Parameter Values
| Parameter | Description |
|---|---|
| searchvalue | Required. The value to search for. |
| length | Optional. The length to search. |
Check if the 11 first characters of a string ends with "world":
let text = "Hello world, welcome to the universe.";
text.endsWith("world", 11);
Note
The endsWith() method is case sensitive.
Browser Support
endsWith() is an ES6 feature (JavaScript 2015).
It is supported in all modern browsers:
| Chrome | Edge | Firefox | Safari | Opera |
| Yes | Yes | Yes | Yes | Yes |
endsWith() is not supported in Internet Explorer.
Complete String Reference
For a complete String reference, go to our:
Complete JavaScript String Reference.
The reference contains descriptions and examples of all string properties and methods.
