title: Setting a default value to an input field in React?
body: <p>I want to set an input field a user can type into with a <code>£</code> sign fixed into that field. The user should not be able to delete or change this sign, but the user should be able to modify what comes after.</p>
  
  <p>e.g.</p>
  
  <ol>
  <li>initial <code>£</code></li>
  <li>user adds <code>10</code>, result: <code>£10</code></li>
  <li>user modified changes <code>10</code> -> <code>5000</code>, result: <code>£5000</code>    </li>
  <li>user deletes everything in the field, result: <code>£</code> remains</li>
  </ol>
  
  <p>The placeholder tag does not work as this is not visible when entering something in the field.
  The default value is also not doing quite what I want.</p>
  
  <pre><code>Place your stake: &lt;input type="text" onChange={this.handleStakeChange}/&gt;
  </code></pre>