title: change value of input made with react from chrome extension
body: <p>I work on Chrome extension, i need to update lot of inputs of an html page made with React from numbers readed from CSV. I cannot update the web site. </p>
  
  <p>-
  An example of input copied from the rendered website :</p>
  
  <pre><code>  &lt;td&gt;&lt;input class="input input_small fpInput" value="29,4"&gt;&lt;/td&gt;
  </code></pre>
  
  <p>-
  How it's made (not sure 100% about that, had to read the uglified js source)</p>
  
  <pre><code>{
      key: "render",
      value: function () {
          return s.a.createElement("input", {
              className: "input input_small fpInput",
              value: this.state.value,
              onChange: this.handleChange,
              onBlur: this.handleSubmit,
              onFocus: this.handleFocus
          })
      }
  }
  </code></pre>
  
  <p>-
  Each time you change the input value a function is called and a POST is made to save it. </p>
  
  <p><strong>I want to trigger the <code>onBlur()</code> or <code>onChange()</code> from my extension after i changed the input value to trigger the POST</strong></p>
  
  <p>I tried this : </p>
  
  <pre><code>var el = document. ... .querySelector('input'); // the selector is simplied of course
  el.value = 321;
  el.onChange();  // ERROR onChange is not a function
  el.onchange();  // ERROR onchange is not a function
  el.handleChange(); // ERROR handleChange is not a function
  </code></pre>
  
  <p>Any idea please ?</p>