حالا اینو امتحان کنید
کد HTML:
<!DOCTYPE html>
<html>
	<head>
		<meta charset="utf-8">
		<title></title>
		<style></style>
	</head>
	<body>
		
		<textarea id='txt1'></textarea>
 
		<button onclick='replaceWords()'>نمایش</button>
 
		<textarea id='txt2'></textarea>
		
	<script>

var changes = {
	'[fars]': 'pars'
}

function replaceWords () {
	
	var replaceString = document.getElementById('txt1').value;
	
	for (var word in changes) {
		var wrd = word.replace("[", "\\[").replace("]", "\\]");
		replaceString = replaceString.replace(new RegExp(wrd, 'g'), changes[word]);
	}
	
	document.getElementById('txt2').value = replaceString;
}
	
	</script>
	</body>
	
</html>