清除在html中按下键的列表

Question

我正在用html进行实时搜索。

我工作得很好，但我遇到了一个小问题，这是我的索引代码：

<form id="quick-search" action="livesearch.php" method="GET" >
<p>
Search:
<input id="qsearch" type="text" name="qsearch" onkeyup="liveSearch()" />
<input type="submit" />
</p>
<div id="searchResults">

</div>
</form>

下面是我的js代码：

function liveSearch()
{
    var url = "livesearch.php";
    var s = document.getElementById('qsearch').value;
    http.open("POST", "livesearch.php?qsearch="+s, true);
    http.onreadystatechange = function() 
    {
        if(http.readyState == 4 && http.status == 200) 
        {
            document.getElementById('searchResults').innerHTML = 'Suggestions are as follow'+http.responseText; 
            //alert(http.responseText);
        } 
    }

    http.send();
}

我得到的结果是正确的，但当我清空完整的输入框时，我将从数据库中获得完整的列表框，在清空输入框时，我想清除列表框

Answer 1

你应该在PHP和用户端保护你的代码。为此，请检查用户确实发送了多少封信：if(s.length < 2 ) return；以防止AJAX请求

function liveSearch()
    {
    var url = "livesearch.php";
    var s = document.getElementById('qsearch').value;
    if(s.length < 2) return; // here You escape if there isn't enough letters to search
    http.open("POST", "livesearch.php?qsearch="+s, true);
    http.onreadystatechange = function() 
    {
        if(http.readyState == 4 && http.status == 200) 
        {
            document.getElementById('searchResults').innerHTML = 'Suggestions are as follow'+http.responseText; 
            //alert(http.responseText);
        } 
    }

    http.send();
}

但请记住，在PHP上也要保护它：

if(count($_REQUEST['qsearch']) < 2) return false;