// source https://jsbin.com/gavovuh

index.html

<script id="jsbin-javascript">
// Challenge 4. Capitalize letters 
// Returns a string with the first letter of every word capitalized
// ex. capitalizeLetters('I love javascript') === 'I love Javascript'

function capitalizeLetters(str)
{
  
  //Takes a lowercase string and splits it
  const strArr = str.toLowerCase().split('');
  
  for(let i = 0; i < strArr.length; i++)
    {
      strArr[i] = strArr[i].substring(0,1).toUpperCase() + strArr[i].substring(1);
    }
  
  return strArr.join(' ')
  
  //////////////
  
}

//Call function
const output = capitalizeLetters('i am building myself up from the bottom');

console.log(output);
</script>


<script id="jsbin-source-javascript" type="text/javascript">// Challenge 4. Capitalize letters 
// Returns a string with the first letter of every word capitalized
// ex. capitalizeLetters('I love javascript') === 'I love Javascript'

function capitalizeLetters(str)
{
  
  //Takes a lowercase string and splits it
  const strArr = str.toLowerCase().split('');
  
  for(let i = 0; i < strArr.length; i++)
    {
      strArr[i] = strArr[i].substring(0,1).toUpperCase() + strArr[i].substring(1);
    }
  
  return strArr.join(' ')
  
  //////////////
  
}

//Call function
const output = capitalizeLetters('i am building myself up from the bottom');

console.log(output);
</script>

jsbin.gavovuh.js

// Challenge 4. Capitalize letters 
// Returns a string with the first letter of every word capitalized
// ex. capitalizeLetters('I love javascript') === 'I love Javascript'

function capitalizeLetters(str)
{
  
  //Takes a lowercase string and splits it
  const strArr = str.toLowerCase().split('');
  
  for(let i = 0; i < strArr.length; i++)
    {
      strArr[i] = strArr[i].substring(0,1).toUpperCase() + strArr[i].substring(1);
    }
  
  return strArr.join(' ')
  
  //////////////
  
}

//Call function
const output = capitalizeLetters('i am building myself up from the bottom');

console.log(output);