title: Cannot manually stretch a draggable div
body: <p>I created a draggable div :</p>
  
  <p><div class="snippet" data-lang="js" data-hide="false" data-console="true" data-babel="false">
  <div class="snippet-code">
  <pre class="snippet-code-js lang-js prettyprint-override"><code>function dragElement(elmnt) {
    var pos1 = 0,
      pos2 = 0,
      pos3 = 0,
      pos4 = 0;
    if (document.getElementById(elmnt.id + "Header")) {
      // if present, the header is where you move the DIV from:
      document.getElementById(elmnt.id + "Header").onmousedown = dragMouseDown;
    } else {
      // otherwise, move the DIV from anywhere inside the DIV: 
      elmnt.onmousedown = dragMouseDown;
    }
  
    function dragMouseDown(e) {
      e = e || window.event;
      e.preventDefault();
      // get the mouse cursor position at startup:
      pos3 = e.clientX;
      pos4 = e.clientY;
      document.onmouseup = closeDragElement;
      // call a function whenever the cursor moves:
      document.onmousemove = elementDrag;
    }
  
    function elementDrag(e) {
      e = e || window.event;
      e.preventDefault();
      // calculate the new cursor position:
      pos1 = pos3 - e.clientX;
      pos2 = pos4 - e.clientY;
      pos3 = e.clientX;
      pos4 = e.clientY;
      // set the element's new position:
      elmnt.style.top = (elmnt.offsetTop - pos2) + "px";
      elmnt.style.left = (elmnt.offsetLeft - pos1) + "px";
    }
  
    function closeDragElement() {
      // stop moving when mouse button is released:
      document.onmouseup = null;
      document.onmousemove = null;
    }
  }
  
  dragElement(document.getElementById("infoVehicule"));</code></pre>
  <pre class="snippet-code-html lang-html prettyprint-override"><code>&lt;div id="infoVehicule"&gt;
    &lt;div id="infoVehiculeHeader"&gt;&lt;/div&gt;
    &lt;p id="infoVehiculeContent"&gt;&lt;/p&gt;
    &lt;p id="infoVehiculeTrajets"&gt;&lt;/p&gt;
  &lt;/div&gt;</code></pre>
  </div>
  </div>
  </p>
  
  <p>At runtime I cannot stretch it to enlarge manually its width. So how to make it possible to stretch this div to enlarge its width manually ?</p>