title: How to allow input type=file to select the same file in react component
body: <p>I have a react component which renders  a <code>&lt;input type="file"&gt;</code> dom to allow user select images from browser. I found that its onChange method not called when I select the same file. After some searching, someone suggests using <code>this.value=null</code> or <code>return false</code> at the end of the onChange method but I have tried it doesn't work. </p>
  
  <p>Below is my code:</p>
  
  <pre><code>&lt;input id="upload" ref="upload" type="file" accept="image/*"
             onChange={(event)=&gt; { this.readFile(event) }}/&gt;
  </code></pre>
  
  <p>Below is what I tried:</p>
  
  <pre><code>&lt;input id="upload" ref="upload" type="file" accept="image/*"
                 onChange={(event)=&gt; { 
                     this.readFile(event) 
                     return false
                }}/&gt;
  </code></pre>
  
  <p>Another one is:</p>
  
  <pre><code>&lt;input id="upload" ref="upload" type="file" accept="image/*"
             onChange={(event)=&gt; { 
                 this.readFile(event) 
                 this.value=null
            }}/&gt;
  </code></pre>
  
  <p>I believe above solutions work for jquery but I don't know how to let it work in reactjs.</p>