选项显示为空白然后选择提交保持值

Is it possible to have the first item in a dropdown list blank and selected by default but when choosing an item in the dropdown list and hitting submit, having that value stay there.

here is an example

<form action="" method="post" />
<SELECT NAME="whatever" id="whatever">
<?php $selected = isset($_POST["whatever"]) && $_POST["whatever"] == 'whatever'; ?>
<option value="" hidden="true" selected="selected"></option>
<OPTION VALUE=1 onclick"selected='selected'">All</OPTION>
</SELECT> 
<input type="submit" name="submit" value="Update"/>
</form>

currently if I hit submit it will change the selected value back to blank.

u may use like this

<form action="" method="post" />
<SELECT NAME="whatever" id="whatever">
<option value="">Select value</option>
<OPTION VALUE=1 <?php if($_POST["whatever"]==1) echo "selected='selected'";?> >All</OPTION>
<OPTION VALUE=2 <?php if($_POST["whatever"]==2) echo "selected='selected'";?> >Value One</OPTION>
</SELECT> 
<input type="submit" name="submit" value="Update"/>
</form>

function html_select($name, $options, $selected= "")
{
    // open <select> tag, set id & name attributes
    $select = "<select id=\"$name\" name=\"$name\">
";

    // populate options to drop down list
    foreach ($options as $value=> $html) {
        $select .= "<option value=\"$value\"";

        // select the selected option
        if ($value == $selected) {
            $select .= " selected=\"selected\"";
        }

        $select .= ">$html</option>
";
    }

    // close </select> tag
    $select .= "</select>";

    // return element
    return $select ;
}

echo html_select("whatever", array("" => "Select Value", "1" => "Value 1"), $_POST["whatever"]);

I hope this help.