How do you substring a string in javascript?
ExamplesExtract a substring from text: Show
let text = "Hello world!"; Try it Yourself » Start at position 2: let result = text.substr(2); Try it Yourself » More examples below. Definition and UsageThe The The To extract characters from the end of the string, use a negative start position. Syntaxstring.substr(start, length) Parameters
Return Value
More ExamplesBrowser Support
ES1 (JavaScript 1997) is fully supported in all browsers:
The Parameters
The index of the first character to include in the returned substring. indexEnd OptionalThe index of the first character to exclude from the returned substring. Return valueA new string containing the specified part of the given string. Description
Any argument value that is less than Any argument value that is
ExamplesUsing substring() The following example uses
Using substring() with length property The following example uses the
The difference between substring() and substr() There are subtle differences between the
Furthermore,
Differences between substring() and slice() The The
If either or both of the arguments are negative or
See the Replacing a substring within a string The following example replaces a substring within a string. It will replace both individual characters and substrings. The function call at the end of the example changes the string
Note that this can result in an infinite loop if A better method for replacing strings is as follows:
The code above serves as an example for substring operations. If you need to replace substrings, most of the time you will want to use
Specifications
Browser compatibilityBCD tables only load in the browser See alsoWhat substring () and substr () will do?The difference between substring() and substr()
substr() 's start index will wrap to the end of the string if it is negative, while substring() will clamp it to 0 . Negative lengths in substr() are treated as zero, while substring() will swap the two indexes if end is less than start .
How do you substring a string?You call the Substring(Int32) method to extract a substring from a string that begins at a specified character position and ends at the end of the string. The starting character position is a zero-based; in other words, the first character in the string is at index 0, not index 1.
How do you half a string in JavaScript?function first_half (str) { if (str. length % 2 == 0) { return str. slice(0, str. length / 2); } return str; } console.
Does string have substring JavaScript?To check if a substring is contained in a JavaScript string:
Call the indexOf method on the string, passing it the substring as a parameter - string. indexOf(substring) Conditionally check if the returned value is not equal to -1. If the returned value is not equal to -1 , the string contains the substring.
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