title: How to replace in Javascript?
body: <p>I can't figure out why this code isn't working. </p>
  
  <p>I want to replace a placeholder with an actual value. Sample code as below:</p>
  
  <pre><code>var str = "ID: :ID:";
  str.replace(":ID:", 0);
  console.log(str);
  </code></pre>
  
  <p>Output:</p>
  
  <pre><code>ID: :ID:
  </code></pre>
  
  <p>This is my <a href="http://jsfiddle.net/B9n79/" rel="nofollow">JSFiddle</a></p>