title: How to set wms parameter (bbox, width, height, x, y)
body: <p>I access the geoserver after creating the wms url. Then I use getFeatureInfo to get the information.
  How do I set the parameters to get multiple layers info?</p>
  
  <p>what is means width, height, x,y, bbox?</p>
  
  <pre><code>var bboxControl = 0.0001;
  
  var bbox = (coordinate[0]-bboxControl) + ',' +  
  (coordinate[1]-bboxControl) + ',' +  
  (coordinate[0]+bboxControl) + ',' +
  (coordinate[1]+bboxControl);
  
  var projection = map.getView().getProjection().getCode();
  
  const parameter = "?SERVICE=WMS
  &amp;VERSION=1.1.1
  &amp;REQUEST=GetFeatureInfo
  &amp;FORMAT=image/png
  &amp;TRANSPARENT=true" 
  + "&amp;QUERY_LAYERS=" + layers
  + "&amp;LAYERS=" + layers
  + "&amp;exceptions=application/vnd.ogc.se_inimage
  &amp;INFO_FORMAT=application/json
  &amp;FEATURE_COUNT=50
  &amp;X=50&amp;Y=50"
  + "&amp;SRS=" + projection
  + "&amp;STYLE=&amp;WIDTH=101&amp;HEIGHT=101"
  + "&amp;BBOX=" + bbox;
  
  $(document).ready(function(){
      $.ajax({
          url: getFeatureInfoUrl + parameter,
          dataType : 'json',
          success: function(result){
              success(result);
          }           
      });
  });
  </code></pre>
  
  <p>This works but not depending on the zoom state.</p>