How to replace all occurrences of a string in JavaScript

Use the JavaScript replace() method

You can use the JavaScript replace() method in combination with the regular expression to find and replace all occurrences of a word or substring inside any string.

Let's check out an example to understand how this method basically works:

<script>
    var myStr = 'freedom is not worth having if it does not include the freedom to make mistakes.';
    var newStr = myStr.replace(/freedom/g, "liberty");
    
    // Printing the modified string
    document.write(newStr);
</script>

However, if the string comes from unknown/untrusted sources like user inputs, you must escape it before passing it to the regular expression. The following example will show you the better way to find and replace a string with another string in JavaScript.

<script>
/* Define function for escaping user input to be treated as 
   a literal string within a regular expression */
function escapeRegExp(string){
    return string.replace(/[.*+?^${}()|[\]\\]/g, "\\$&");
}
 
/* Define functin to find and replace specified term with replacement string */
function replaceAll(str, term, replacement) {
  return str.replace(new RegExp(escapeRegExp(term), 'g'), replacement);
}
 
/* Testing our replaceAll() function  */
var myStr = 'if the facts do not fit the theory, change the facts.';
var newStr = replaceAll(myStr, 'facts', 'statistics')
 
// Printing the modified string
document.write(newStr);
</script>