一页上有两个下拉框而没有提交

Question

我确实遇到一个页面上有两个下拉框的问题。因为我必须在没有提交的情况下工作我在“”中使用“onblur = document.getElementById.submit”。这工作正常，但只适用于一个下拉框。对于两个表单使用相同（相等）的代码将导致在选择form2和visa verse中的项目时销毁form1的条目。 形式-1：

<form id="formunit" name="formunit" method="post" action="" >

    <select name="cbo_unit" required="required" form="formunit" style="width:100pt" onblur="document.getElementById('formunit').submit();">
        <option value="0">--select--</option>
        <?php
        if ($_POST["cbo_unit"] == "MH") {
            echo "<option value=\"MH\" selected=\"selected\">Motorhome</option>";
        } else {
            echo "<option value=\"MH\">Motorhome</option>";
        }
        if ($_POST["cbo_unit"] == "RT") {
            echo "<option value=\"RT\" selected=\"selected\">Racetruck</option>";
        } else {
            echo "<option value=\"RT\">Racetruck</option>";
        }
        ?>
    </select>

    <?php
        if(isset($_POST['cbo_unit']) && $_POST['cbo_unit'] > '') {
            $unit = $_POST['cbo_unit']; 
        }
    ?>
</form>

表2：

<?php
    fc_opendb("1","something",$connect);
    $dbtable = "course";
    $result = mysqli_query($GLOBALS["connect"],"SELECT * FROM " . $dbtable . " WHERE blocked = 'no' ORDER BY matchcode ASC");
?>

<form id="formcourse" name="formcourse" method="post" action="" >

    <select name="cbo_course" required="required" form="formcourse" style="width:130pt" onblur="document.getElementById('formcourse').submit();">
        <option value="0">--select--</option>
        <?php
        while ($row = mysqli_fetch_assoc($result)) {
            if ($row['matchcode'] == $_POST['cbo_course']) {
                $selected = "selected";
            } else {
                $selected = "";
            }

            echo '<option value="' . $row['matchcode'] . '"' . $selected . '>' . utf8_encode($row['name']) . ' - ' . utf8_encode($row['place']) . '</option>'."\n";
        }
        ?>
    </select>
    <?php
        if(isset($_POST['cbo_course']) && $_POST['cbo_course'] > '') {
            $course = $_POST['cbo_course'];
        } 
        mysqli_close($GLOBALS["connect"]);
    ?>
</form>