String in DSA Using JavaScript Last Updated : 23 Jul, 2025 Comments Improve Suggest changes Like Article Like Report A string in JavaScript is a sequence of characters enclosed in single ('), double ("), or backticks (`). Strings in JavaScript are immutable, meaning their contents cannot be changed after creation. Any operation that modifies a string actually creates a new string.Example: JavaScript let s = "GfG"; console.log(s[0]); console.log(s.length); OutputG 3 Common String Methods in JavaScript:length – Returns the number of characters in a string.charAt(index) – Returns the character at the specified index.slice(start, end) – Extracts a section of a string and returns it as a new string.substring(start, end) – Similar to slice(), but does not accept negative indices.toUpperCase() / toLowerCase() – Converts the string to uppercase or lowercase.trim() – Removes whitespace from both ends of a string.replace(searchValue, newValue) – Replaces a specified value with another value in a string.split(separator) – Splits a string into an array based on a specified separator.includes(substring) – Checks if a string contains a given substring, returning true or false.concat(str1, str2, ...) – Joins two or more strings together.Please refer JavaScript String Methods for more methods. Easy Problems Problem On String using JavaScript Reverse a String Palindrome Check Check for Subsequence Check Anagram Reverse Words Isomorphic Strings Check Pangram or notMedium Problems On String in JavaScriptImplement AtoiValidate an IP addressFind the largest word in dictionaryEqual 0, 1, and 2Longest Palindromic SubsequenceLongest substring without RepeatingHard Problems On String in JavaScriptSearch Pattern (KMP-Algorithm)Search Pattern (Rabin-Karp Algorithm)Shortest Common SupersequenceNumber of words with K maximum distinct vowelsLongest substring to form a PalindromeLongest Valid Parenthesis Strings in JavaScript Visit Course Comment More info A aayushmohansinha Follow Improve Article Tags : Technical Scripter JavaScript Web Technologies Technical Scripter 2022 javascript-string JavaScript-DSA +2 More Explore JavaScript BasicsIntroduction to JavaScript4 min readVariables and Datatypes in JavaScript6 min readJavaScript Operators5 min readControl Statements in JavaScript4 min readArray & StringJavaScript Arrays7 min readJavaScript Array Methods7 min readJavaScript Strings5 min readJavaScript String Methods9 min readFunction & ObjectFunctions in JavaScript5 min readJavaScript Function Expression3 min readFunction Overloading in JavaScript4 min readObjects in JavaScript4 min readJavaScript Object Constructors4 min readOOPObject Oriented Programming in JavaScript3 min readClasses and Objects in JavaScript4 min readWhat Are Access Modifiers In JavaScript ?5 min readJavaScript Constructor Method7 min readAsynchronous JavaScriptAsynchronous JavaScript2 min readJavaScript Callbacks4 min readJavaScript Promise4 min readEvent Loop in JavaScript4 min readAsync and Await in JavaScript2 min readException HandlingJavascript Error and Exceptional Handling6 min readJavaScript Errors Throw and Try to Catch2 min readHow to create custom errors in JavaScript ?2 min readJavaScript TypeError - Invalid Array.prototype.sort argument1 min readDOMHTML DOM (Document Object Model)9 min readHow to select DOM Elements in JavaScript ?3 min readJavaScript Custom Events4 min readJavaScript addEventListener() with Examples9 min readAdvanced TopicsClosure in JavaScript4 min readJavaScript Hoisting6 min readScope of Variables in JavaScript3 min readJavaScript Higher Order Functions7 min readDebugging in JavaScript4 min read Like