Make your selection


<form class="form-horizontal" action="" method="post">

<select class="form-control" id="selFeeder" name="selFeed" onChange="this.form.submit();" required> <option value="0">feeder type</option> <option value="55" <?php if($_POST['selFeed']=='55') echo 'selected="selected"';?> >SXM50</option> <option value="106" <?php if($_POST['selFeed']=='106') echo 'selected="selected"';?> >SXM100</option> <option value="156" <?php if($_POST['selFeed']=='156') echo 'selected="selected"';?> >SXM140</option> <option value="220" <?php if($_POST['selFeed']=='220') echo 'selected="selected"';?> >SXM200</option> <option value="253" <?php if($_POST['selFeed']=='253') echo 'selected="selected"';?> >SX240</option> <option value="359" <?php if($_POST['selFeed']=='359') echo 'selected="selected"';?> >SX340</option> </select>

<select class="form-control" id="selLens" name="selLens"> <option value="0">focal length [mm]</option> <option value="12.5" <?php if($_POST['selLens']=='12.5') echo 'selected="selected"';?> >12.5mm</option> <option value="16" <?php if($_POST['selLens']=='16') echo 'selected="selected"';?> >16mm</option> <option value="25" <?php if($_POST['selLens']=='25') echo 'selected="selected"';?> >25mm</option> <option value="35" <?php if($_POST['selLens']=='35') echo 'selected="selected"';?> >35mm</option> <option value="50" <?php if($_POST['selLens']=='50') echo 'selected="selected"';?> >50mm</option> <option value="75" <?php if($_POST['selLens']=='75') echo 'selected="selected"';?> >75mm</option> </select>

<select class="form-control" id="selCam" name="selCam"> <option value="0">camera model</option> <option value="2.7" <?php if($_POST['selCam']=='2.7') echo 'selected="selected"';?> >In-Sight 7600</option> <option value="4.608" <?php if($_POST['selCam']=='4.608') echo 'selected="selected"';?> >In-Sight 7801</option> <option value="5.4" <?php if($_POST['selCam']=='5.4') echo 'selected="selected"';?> >In-Sight 7802</option> </select>