title: Concatenating string with number in Javascript
body: <p>I'm trying to create a simple calculator in Javascript. I have an array named expression
      <code>chunk[0] = 12</code>
      <code>chunk[1] = +</code> (the "+" sign)
      <code>chunk[1] = 5</code></p>
  
  <p>I used a for loop to loop through the chunks (chunk[]) and join then into a single expression as follows:-</p>
  
  <pre><code>equation = ""; // To make var equation a string
  
  for(i = 0; i &lt;= length; i++)
  {
      equation = equation + expression[i];
      alert(expression[i]);
  }
  
  alert(equation);
  </code></pre>
  
  <p><code>alert(expression[i])</code> showed values 12, + and 5.
  But alert(equation) showed 125 (instead of "12+5"). I need the variable equation to be "12+5" so that I can later call eval(equation) and get the value of 12+5.</p>
  
  <p>What am I doing wrong here?</p>