- JavaScript Basics
- JavaScript Tutorial
- JavaScript: where to write
- JavaScript: how to display
- JavaScript: keywords
- JavaScript: comments
- JavaScript: variables
- JavaScript: operators
- JavaScript: data types
- JavaScript Conditional Statements
- JavaScript: if-else
- JavaScript: switch
- JavaScript: for loop
- JavaScript: while loop
- JavaScript: do-while loop
- JavaScript: break and continue
- JavaScript Popup Boxes
- JavaScript: alert box
- JavaScript: confirm box
- JavaScript: prompt box
- JavaScript Popular Topics
- JavaScript: functions
- JavaScript: innerHTML
- JavaScript: getElementById()
- JavaScript: getElementsByClassName()
- JavaScript: getElementsByName()
- JavaScript: getElementsByTagName()
- JavaScript: querySelector()
- JavaScript: querySelectorAll()
- JavaScript: document.write()
- JavaScript: console.log()
- JavaScript: boolean
- JavaScript: events
- JavaScript: Math object
- JavaScript: Math.random()
- JavaScript: Number()
- JavaScript: parseInt()
- JavaScript: parseFloat()
- JavaScript Arrays
- JavaScript: array
- JavaScript: find length of array
- JavaScript: add element at beginning
- JavaScript: add element at end
- JavaScript: remove first element
- JavaScript: remove last element
- JavaScript: get first index
- JavaScript: get last index
- JavaScript: reverse an array
- JavaScript: sort an array
- JavaScript: concatenate arrays
- JavaScript: join()
- JavaScript: toString()
- JavaScript: from()
- JavaScript: check if value exists
- JavaScript: check if array
- JavaScript: slice an array
- JavaScript: splice()
- JavaScript: find()
- JavaScript: findIndex()
- JavaScript: entries()
- JavaScript: every()
- JavaScript: fill()
- JavaScript: filter()
- JavaScript: forEach()
- JavaScript: map()
- JavaScript Strings
- JavaScript: string
- JavaScript: length of string
- JavaScript: convert to lowercase
- JavaScript: convert to uppercase
- JavaScript: string concatenation
- JavaScript: search()
- JavaScript: indexOf()
- JavaScript: search() vs. indexOf()
- JavaScript: match()
- JavaScript: match() vs. search()
- JavaScript: replace()
- JavaScript: toString()
- JavaScript: String()
- JavaScript: includes()
- JavaScript: substr()
- JavaScript: slice string
- JavaScript: charAt()
- JavaScript: repeat()
- JavaScript: split()
- JavaScript: charCodeAt()
- JavaScript: fromCharCode()
- JavaScript: startsWith()
- JavaScript: endsWith()
- JavaScript: trim()
- JavaScript: lastIndexOf()
- JavaScript Date and Time
- JavaScript: date and time
- JavaScript: Date()
- JavaScript: getFullYear()
- JavaScript: getMonth()
- JavaScript: getDate()
- JavaScript: getDay()
- JavaScript: getHours()
- JavaScript: getMinutes()
- JavaScript: getSeconds()
- JavaScript: getMilliseconds()
- JavaScript: getTime()
- JavaScript: getUTCFullYear()
- JavaScript: getUTCMonth()
- JavaScript: getUTCDate()
- JavaScript: getUTCDay()
- JavaScript: getUTCHours()
- JavaScript: getUTCMinutes()
- JavaScript: getUTCSeconds()
- JavaScript: getUTCMilliseconds()
- JavaScript: toDateString()
- JavaScript: toLocaleDateString()
- JavaScript: toLocaleTimeString()
- JavaScript: toLocaleString()
- JavaScript: toUTCString()
- JavaScript: getTimezoneOffset()
- JavaScript: toISOString()
- JavaScript Regular Expression
- JavaScript: regular expression
- JavaScript: RegEx . (dot)
- JavaScript: RegEx \w and \W
- JavaScript: RegEx \d and \D
- JavaScript: RegEx \s and \S
- JavaScript: RegEx \b and \B
- JavaScript: RegEx \0
- JavaScript: RegEx \n
- JavaScript: RegEx \xxx
- JavaScript: RegEx \xdd
- JavaScript: RegEx quantifiers
- JavaScript: RegEx test()
- JavaScript: RegEx lastIndex
- JavaScript: RegEx source
- JavaScript Programs
- JavaScript Programs
JavaScript replace(): Replace String with Another
The JavaScript replace() method is used when we need to replace a string using either the string itself or a regular expression. For example:
<!DOCTYPE html>
<html>
<body>
<p id="xyz"></p>
<script>
let myString = "I love JavaScript. JavaScript is a great language.";
let myNewString = myString.replace("JavaScript", "Python");
document.getElementById("xyz").innerHTML = myNewString;
</script>
</body>
</html>Let me modify the above example to replace all occurrences of the specified string (JavaScript), using, of course, a regular expression:
<!DOCTYPE html>
<html>
<body>
<p id="xyz"></p>
<script>
let myString = "I love JavaScript. JavaScript is a great language.";
let myNewString = myString.replace(/JavaScript/g, "Python");
document.getElementById("xyz").innerHTML = myNewString;
</script>
</body>
</html>The g in /JavaScript/g stands for global, which is a modifier used in regular expression to get all matches. Therefore, both the word (JavaScript) from the above example were replaced by Python.
Note: If there is only one occurrence of the specified value, that has to be replaced with another one. Or if you want to replace only the first occurrence of the specified old value with a new one, then only go with a direct string. Otherwise, always prefer to replace strings using regular expressions.
JavaScript replace() syntax
The syntax of the replace() method in JavaScript is:
string.replace(oldValue, newValue)
Both the arguments, oldValue and newValue, are required.
The replace() method returns a new string that is equal to the specified string, except that its oldValue will be replaced with newValue.
Note: Use regular expressions along with g and i (which stand for case-insensitive) modifiers to replace all occurrences of oldValue with newValue without caring about the case (upper and lowercase) of the characters.
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