AJAX - 在列表框中选择更改PHP事件

Question

？我怎样才能查询，以便对任何列表框中选择更改

if(isset($_POST['select'])){ 
$newselection=$_POST['select']; 
$query = "SELECT count(*) FROM listings where description=" . $newselection. ""; 
$result = mysql_query($query); 
while($row = mysql_fetch_array($result, MYSQL_ASSOC)) 
{ 
    echo "Number of rows: {$row['count(*)']}"; 
} 
} 

目前当提交按钮被按下

我试图避免它只能运行JS ..

*我也有其他查询运行Ajax

if(isset($_POST['button1'])){ 
$selection=$_POST['select']; 
$queryres = "SELECT * FROM listings where description=" . $selection. ""; 
$resultres = mysql_query($queryres); 
while($rowres = mysql_fetch_array($resultres, MYSQL_ASSOC)) 
{ 

    echo "<div style='position: absolute; left: 294px; top: 16px;' title='Site map' class='myclass'> <img src={$rowres['picture1']} alt=''/></div>" ; 
    echo "<div style='position: absolute; left: 294px; top: 116px;' class='myclass'>Number:{$rowres['number']} <br>Description : {$rowres['description']} <br><br></div>" ; 
} 
} 

Answer 1

试试这个（它无关，与PHP代码，它的HTML）

<option onchange="this.submit();"> 

Answer 2

JS是用户点击提交按钮的唯一选择。像<select onchange="submit();">可能就足够了。