本文就是和大家分享一款由php结合ajax实现的无刷新留言板，先给大家看一下最后的效果图：
数据库连接代码如下：
<?php$conn = @mysql_connect("localhost","root","root") or die ("MySql连接错误");mysql_select_db("demo",$conn);mysql_query("set names 'utf8'");?>
index.php文件代码如下：
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd"><html xmlns="http://www.w3.org/1999/xhtml"><head><meta http-equiv="Content-Type" content="text/html; charset=utf-8"><link href="bbs.css" type="text/css" rel="stylesheet"><title>无刷新显示回帖</title><script src="bbs.js" type="text/javascript"></script></head><body><h1>无刷新显示回帖</h1><div id="thread"><?phpinclude("conn.php");$sql = "select * from `bbs_post` where `threadid` ='1' order by id asc";$query =mysql_query($sql);while($row = mysql_fetch_array($query)){ ?> <div class="post" id="post<?php echo $row['id'];?>"> <div class="post_title"><?php echo $row['title'];?> [<?php echo $row['username'];?>]</div> <div class="post_content"><pre><?php echo $row['content'];?></pre></div> </div><?php}?></div><table class="reply"><tr> <td colspan="2" class="title">回帖<input type="hidden" name="threadid" id="threadid" value="1"></td></tr><tr> <td>姓名：</td> <td><input type="text" name="username" id="username"></td></tr><tr> <td>标题：</td> <td><input type="text" name="post_title" id="post_title"></td></tr><tr> <td>内容：</td> <td><textarea name="post_content" id="post_content"></textarea></td></tr><tr> <td colspan="2"><input type="button" onclick="submitPost()" value="提交"></td></tr></table></body></html>
bbspost.php文件代码如下
<?phpinclude("conn.php");$title = $_POST["title"]; //获取title$content = $_POST["content"]; //获取content$username = $_POST["username"]; //获取username$threadId = $_POST["threadid"]; //获取threadid$sql="insert into bbs_post (title,content,username,threadid) " . "values ('$title','$content','$username','$threadId')"; mysql_query($sql); //传回最后一次使用 INSERT 指令的 ID$responseId=mysql_insert_id();echo $responseId;?>
bbs.js文件里面包括了大量ajax文件，代码如下
//先创建一个空的bbs.js文件，并修改其属性为utf-8，才能保存中文。var xmlHttp; //用于保存XMLHttpRequest对象的全局变量var username; //用于保存姓名var title; //用于保存标题var content; //用于保存内容var threadid; //用于保存主题编号//用于创建XMLHttpRequest对象function createXmlHttp() { //根据window.XMLHttpRequest对象是否存在使用不同的创建方式 if (window.XMLHttpRequest) { xmlHttp = new XMLHttpRequest(); //FireFox、Opera等浏览器支持的创建方式 } else { xmlHttp = new ActiveXObject("Microsoft.XMLHTTP");//IE浏览器支持的创建方式 }}//提交回帖到服务器function submitPost() { //获取帖子中姓名、标题、内容、主题编号四部分信息 username = document.getElementById("username").value; title = document.getElementById("post_title").value; content = document.getElementById("post_content").value; threadid = document.getElementById("threadid").value; if (checkForm()) { createXmlHttp(); //创建XMLHttpRequest对象 xmlHttp.onreadystatechange = submitPostCallBack; //设置回调函数 xmlHttp.open("POST", "bbspost.php", true); //发送POST请求 //设置POST请求体类型 xmlHttp.setRequestHeader("Content-type","application/x-www-form-urlencoded"); xmlHttp.send("username=" + encodeURI(username) + "&title=" + encodeURI(title) + "&content=" + encodeURI(content) + "&threadid=" + threadid); //发送包含四个参数的请求体 }}//检查表单是否内容已填写完毕function checkForm() { if (username == "") { alert("请填写姓名"); return false; } else if (title == "") { alert("请填写标题"); return false; } else if (content == "") { alert("请填写内容"); return false; } return true;}//获取查询选项的回调函数function submitPostCallBack() { if (xmlHttp.readyState == 4) {alert(xmlHttp.responseText); createNewPost(xmlHttp.responseText); }}//创建新的回帖function createNewPost(postId) { //清空当前表单中各部分信息 document.getElementById("post_title").value = ""; document.getElementById("post_content").value = ""; document.getElementById("username").value = ""; var postDiv = createDiv("post", ""); //创建回帖的外层div postDiv.id = "post" + postId; //给新div赋id值 var postTitleDiv = createDiv("post_title", title + " [" + username + "]"); //创建标题div var postContentDiv = createDiv("post_content", "<pre>" + content + "</pre>"); //创建内容div postDiv.appendChild(postTitleDiv); //在外层div追加标题 postDiv.appendChild(postContentDiv); //在外层div追加内容 document.getElementById("thread").appendChild(postDiv); //将外层div追加到主题div中}//根据className和text创建新的divfunction createDiv(className, text) { var newDiv = document.createElement("div"); newDiv.className = className; newDiv.innerHTML = text; return newDiv;}
bbs.css文件如下：
body, td, input, textarea { font-family:Arial; font-size:12px;}#thread { border:1px solid black; width:300px; margin-bottom:10px;}#statusDiv { border:1px solid #999; background:#FFFFCC; width:100px; position:absolute; top:50%; left:50%; margin:-50px 0 0 -100px; width:280px;}div.post { border-bottom:1px solid black; padding:5px;}div.post_title { border-bottom:1px dotted #0066CC; font-weight:bold;}div.post_content { font-size:12px; margin:5px;}table.reply { border-collapse:collapse; width:300px;}table.reply td { border:1px solid black; padding:3px;}table.reply td.title { background:#003366; color:#FFFFFF;}input, textarea { border:1px solid black;}textarea { width:200px; height:50px;}pre { margin:0;}
以上就是本文的全部内容，希望对大家的学习有所帮助。
