function toLowerFirst(s) {

    return s.substr( 0, 1 ).toLowerCase() + s.substr( 1 );

}

​

function camelize(str) {

  return str.replace(/(?:^\w|[A-Z]|\b\w)/g, function(letter, index) {

    return index == 0 ? letter.toLowerCase() : letter.toUpperCase();

  }).replace(/\s+/g, '');

}

​

​

function test(name, func ){

  console.time(name);

  for(var i = 0; i < 1000; i++){

    func("Abcdefg");

  }

  console.timeEnd(name);

}

​

console.log(camelize('AbC'));

console.log(toLowerFirst('AbC'));

​

test('camelize', camelize);

test('toLower', toLowerFirst);