regexhelp.js

function replaceASingleCharacter(str, singleCharacter, replaceWith) {
	// put regex replace here
	// something like return str.replace(/blahblahregex/,replaceWith);
}

var result1 = replaceASingleCharacter("This X should be replaced","X","Y");
if(result1 != "This Y should be replaced") {
	console.log("fail 1");
}

var result2 = replaceASingleCharacter("These XX should NOT be replaced","X","Y");
if(result2 != "These XX should NOT be replaced") {
	console.log("fail 2");
}

var result3 = replaceASingleCharacter("This X should be replaced, but the XX should not be","X","Y");
if(result3 != "This Y should be replaced, but the XX should not be") {
	console.log("fail 3");
}