Jun 22, 2009 · The answer by josh and maleki will return true on both upper and lower case if the character or the whole string is numeric. making the result a false result. example using josh var character = '5'; if (character == character.toUpperCase()) { alert ('upper case true'); } if (character == character.toLowerCase()){ alert ('lower case true'); }

Jul 5, 2024 · One can use regular expressions to check whether the letters are in upper case or lower case. Syntax: Example: Demonstrating the use of the regular expression to check the case of the letter. function checkCase(character) { return (/[A-Z]/.test(character)) ? 'Uppercase' : 'Lowercase'; } console.log(checkCase("G")) console.log(checkCase("g"))

May 14, 2010 · Consider a JavaScript method that needs to check whether a given string is in all uppercase letters. The input strings are people's names. The current algorithm is to check for any lowercase letters. //pattern for finding whether any lowercase alpha characters exist. var allLowercase; . return allLowercase.test(input);

Mar 3, 2024 · To check if a letter in a string is uppercase or lowercase: Use the toUpperCase() method to convert the letter to uppercase. Compare the letter to itself. If the comparison returns true, the letter is uppercase, otherwise, it's lowercase. We used the String.toUpperCase () method to convert the character to uppercase so we can compare it.

Jul 16, 2024 · We have given string str of length N, the task is to check whether the given string contains uppercase alphabets, lowercase alphabets, special characters, and numeric values or not. If the string contains all of them, then returns “true”.

Dec 20, 2021 · The toLowerCase() method converts a given string into a lowercase string. In the following example, we have one global variable that holds a string. Upon click of a button, we will check whether it is in lowercase or not and display the result on the screen.

Dec 20, 2023 · In order to check if a string is uppercase, we can convert the string to uppercase using String.prototype.toUpperCase() and compare it to the original string. Conversely, we can do the same for lowercase strings, comparing the original string with the output of String.prototype.toLowerCase().

Mar 24, 2022 · You can detect whether a given input is a lowercase string in JavaScript using a comparison of the given value against its lowercased pendant. JavaScript provides a toLowerCase method on string values.

Dec 2, 2019 · To test if a letter in a string is uppercase or lowercase using javascript, you can simply convert the char to its respective case and see the result. if (!isNaN(ch * 1)){ return 'ch is numeric'; else { if (ch == ch.toUpperCase()) { return 'upper case'; if (ch == ch.toLowerCase()){ return 'lower case'; This will give the output −.

Feb 26, 2025 · Write a JavaScript program to check whether a string is lower case or not. Convert the given string to lower case, using String.prototype.toLowerCase () and compare it to the original. // Check if the given string 'str' is equal to its lowercase version. str === str.toLowerCase();