Question

Is there an easy equivalent to this in JavaScript?

$find = array("<", ">", "\n");
$replace = array("&lt;", "&gt;", "<br/>");

$textarea = str_replace($find, $replace, $textarea); 

This is using PHP’s str_replace, which allows you to use an array of words to look for and replace. Can I do something like this using JavaScript / jQuery?

...
var textarea = $(this).val();

// string replace here

$("#output").html(textarea);
...

Answer 1

You could extend the String object with your own function that does what you need (useful if there’s ever missing functionality):

String.prototype.replaceArray = function(find, replace) {
  var replaceString = this;
  for (var i = 0; i < find.length; i++) {
    replaceString = replaceString.replace(find[i], replace[i]);
  }
  return replaceString;
};

For global replace you could use regex:

String.prototype.replaceArray = function(find, replace) {
  var replaceString = this;
  var regex; 
  for (var i = 0; i < find.length; i++) {
    regex = new RegExp(find[i], "g");
    replaceString = replaceString.replace(regex, replace[i]);
  }
  return replaceString;
};

To use the function it’d be similar to your PHP example:

var textarea = $(this).val();
var find = ["<", ">", "\n"];
var replace = ["&lt;", "&gt;", "<br/>"];
textarea = textarea.replaceArray(find, replace);