Don't clear form after you submit - HTML

I want the SID value in the form below to stay as what I entered when you press submit so that you don't have to enter it for each of the drop down options. Can this be easily done? Here is my html:

            <a href ="#" class = "navbar-brand">User Reports</a>

            </div>
    </div>
    <!--Form-->
    <br/><br/><br/>

    <div class = "container">
    <div class = "row">
    <div class = "col-md-12"></div>

    <h2>Customer Usage Info </h2> <hr/>


    <form class = "form-horizontal" method="post" action="">
        <div class = "form-group">
            <label for="Enter SID" class="col-sm-2 control-label">Enter SID of Customer</label> 
            <div class = "col-sm-4">
            <input type = "text" class = "form-control" placeholder ="Enter SID . . ." name="SID"/>
            </div>                      
    </div>

        <div class = "form-group">
            <label for="Enter ID" class="col-sm-2 control-label">What Info are you looking for?</label> 
            <div class = "col-sm-8">
            <select = "form-control" name = "mydropdown" >
                <option value = "1">CPU</option>
                <option value ="2">Memory</option>
                <option value="3">Storage</option>
                <option value = "4">VMs</option>
            </select>
            </div>
        </div>  

        <div class = "form-group">
            <div class ="date">
            <label for="Start Date:" class="col-sm-2 control-label">Start Date</label> 
            <div class = "col-sm-4">
            <input class ="datepicker" type ="text" placeholder ="DD/MM/YYYY" name = "SDate">
            </div>
            </div>
        </div>

        <div class = "form-group">
            <div class ="date">
            <label for="End Date:" class="col-sm-2 control-label">End Date</label> 
            <div class = "col-sm-4">
            <input class ="datepicker" type ="text" placeholder ="DD/MM/YYYY" name = "EDate">
            </div>
            </div>
        </div>

        <div class = "form-group">
            <div class = "col-sm-offset-2 col-sm-8">
            <button type= "submit" class = "btn btn-primary" >Submit</button>
            </div>
            </div>  
            </div>  


    </form>

Thanks