I'm getting this error in Php file Parse error: syntax error, unexpected '=' [duplicate]

<form action="/zoznam.php?stav=<?php= $stav ?>" method="post">
                    <div class="input-group">
                        <input type="text" class="form-control" id="filter" name="filter"
                               value= " <?php= htmlentities($filter) ?> "
                               placeholder="Filter na meno / priezvisko / rodné číslo">
                        <span class="input-group-btn">
                        <input type="submit" value="Filtruj" class="btn btn-primary">
                     </span>
                    </div>
                </form>

On line 4 value= " i'm getting error unexpected '=' syntax error I dont know how I've tried many ways by removing = but getting errors