本文描述如何在網頁上實現一個簡單的留言板功能,僅支持文字留言。
開發環境:dreamweaverCC html +jscirpt + php
前置條件:1、一個簡單的網站已經搭建完畢,支持用戶登錄網站。
2、用戶已登錄網站。
實現步驟:
一、新建留言板網頁
1、新建網頁:whiteboard.html
留言板(js-div-whiteboard)分爲三個部分:
留言列表:(js-div-whiteboard-messages)、無留言提示:(js-div-whiteboard-empty-hint )、提交新留言:(js-div-whiteboard-input),三個div自上而下垂直排列。
html:
<div class = "js-div-whiteboard ">
<div class = "js-div-whiteboard-messages">
</div>
<div class = "js-div-whiteboard-empty-hint">
</div>
<div class = "js-div-whiteboard-input style-margin-top">
</div>
</div>
2、留言列表 js-div-whiteboard
留言列表分爲 菜單(js-div-whiteboard-menu)和 留言內容(js-ul-whiteboard-message-list)兩部分。
菜單:上一頁 、下一頁。
留言內容:作者10% + 留言80% + 日期10%, 三項內容水平排列,寬度爲10%-80%-10%。 每條留言之間有水平線分割。
以上兩項內容自上而下垂直排列。
html
<div class = "js-div-whiteboard-messages">
<div class="js-div-whiteboard-menu">
<span> </span>
<span class = "js-whiteboard-up-page ">上一頁</span>
<span> </span>
<span class = "js-whiteboard-down-page ">下一頁</span>
<hr class = "style-hr-full">
</div>
<ul class="js-ul-whiteboard-message-list style-li-notice-text style-ul-user-menu">
<li class = "style-fontsize-15">
<span class = "style-li-whiteboard-user style-fontsize-15-center">user1</span>
<span class = "style-li-whiteboard-message">喫瓜羣衆三號。</span>
<span class = "style-li-whiteboard-date style-fontsize-15-center">01-02</span>
</li>
<hr class = "style-hr-full">
<li>
<span class = "style-li-whiteboard-user">user2</span>
<span class = "style-li-whiteboard-message">喫瓜羣衆二號。</span>
<span class = "style-li-whiteboard-date">01-02</span>
</li>
<hr class = "style-hr-full">
</ul>
</div>
3、無留言提示:(js-div-whiteboard-empty-hint )
<div class = "js-div-whiteboard-empty-hint">
<span class = "style-li-whiteboard-message"> 留言板還是空的哦!</span>
</div>
4、提交新留言:(js-div-whiteboard-input)
包含 textarea (js-whiteboard-textarea-input) 和 button(js-button-whiteboard-submit)兩部分,上下垂直排列。
html
<div class = "js-div-whiteboard-input style-margin-top">
<textarea class = "js-whiteboard-textarea-input" rows="5" cols="100" maxlength = "400" placeholder="說點什麼吧……" style = "resize: none"></textarea><br/><br/>
<button class = " js-button-whiteboard-submit" > 提 交 </button>
</div>
5、最後添加一些css設置,頁面結果
html:
<div class = "js-div-whiteboard ">
<div class = "js-div-whiteboard-messages">
<div class="js-div-whiteboard-menu style-fontsize-15">
<span> </span>
<span class = "js-whiteboard-up-page ">上一頁</span>
<span> </span>
<span class = "js-whiteboard-down-page ">下一頁</span>
<hr class = "style-hr-full">
</div>
<ul class="js-ul-whiteboard-message-list style-li-notice-text style-ul-user-menu">
<li class = "style-fontsize-15">
<span class = "style-li-whiteboard-message">我在這裏安靜地喫個瓜。</span>
<span class = "style-li-whiteboard-user style-fontsize-15-center">user1</span>
<span class = "style-li-whiteboard-date style-fontsize-15-center">01-02</span>
</li>
<hr class = "style-hr-full">
<li>
<span class = "style-li-whiteboard-message">還不錯哦!</span>
<span class = "style-li-whiteboard-user">user2</span>
<span class = "style-li-whiteboard-date">01-02</span>
</li>
<hr class = "style-hr-full">
</ul>
</div>
<div class = "js-div-whiteboard-empty-hint style-margin-bottom style-margin-top">
<span class = "style-li-whiteboard-message style-margin-bottom style-margin-top"> 留言板還是空的哦!</span>
</div>
<div class = "js-div-whiteboard-input style-margin-top">
<textarea class = "js-whiteboard-textarea-input style-fontsize-20" rows="5" cols="100" maxlength = "400" placeholder="說點什麼吧……" style = "resize: none"></textarea><br/><br/>
<button class = "style-fontsize-20 js-button-whiteboard-submit" > 提 交 </button>
</div>
</div>
至此留言板界面完成。
二、數據庫設計
本網站數據庫採用阿里雲ecs 自建庫。表名稱:whiteboard_messages
結構如下:
預置數據庫內容如下:
三、留言板功能實現
1、服務器端:支持網頁端查詢數據庫內的留言信息
getBoardmessages.php:
<?php
$offset = $_POST['offset'];
$conn = mysqli_connect("localhost","root","","Learn") or die("連接失敗");
mysqli_query($conn,"set names utf8");
$result = mysqli_query($conn,"select * from whiteboard_messages order by creat_time DESC limit 2 offset $offset ");
$messageArray = array();
while ($row = mysqli_fetch_array($result))
{
$tempArray = array('id'=>$row[id],'message'=>$row[message],'author'=>$row[author],'author_id'=>$row[author_id],'creat_time'=>$row[creat_time]);
array_push($messageArray,$tempArray);
}
//把消息返回前端
if (sizeof($messageArray)> 0)
{
echo json_encode($messageArray,JSON_UNESCAPED_UNICODE);
}
else
{
echo "no message";
}
?>
2、網頁端:刷新頁面時,顯示已有留言
功能:每次打開或刷新頁面時,從數據庫中讀取最新的2條信息,按照日期降序排列。
沒有留言時,顯示空白留言提示。
jscpript 核心代碼:
$.ajax({
url:"http://www.xxx.cn/php/getBoardmessages.php",
type:"POST",
async: false,//設置爲同步操作就可以給全局變量賦值成功
data:{"info":"get_message","offset":0},
success:function(data){
console.log(data);
if (data == "no message")
{
$(".js-div-whiteboard-empty-hint").attr("style","display:block;");
$(".js-div-whiteboard-messages").attr("style","display:none;");
return;
}
$(".js-div-whiteboard-empty-hint").attr("style","display:none;");
$(".js-div-whiteboard-messages").attr("style","display:block;");
var info = JSON.parse(data);
global_whiteboard_message_list = info;//
displayWhiteboardMessageList();
},
error:function(xhr){alert("錯誤提示: " + xhr.status + " " + xhr.statusText);}
});
function displayWhiteboardMessageList()
{
var text = "";
$(".js-ul-whiteboard-message-list").empty();
for (var i = 0;i < global_whiteboard_message_list.length;i++)
{
text = text
+ "<li class = \"style-fontsize-15\"><span class = \"style-li-whiteboard-user style-fontsize-15-center\">"
+ global_whiteboard_message_list[i].author
+ "</span><span class = \"style-li-whiteboard-message\">"
+ global_whiteboard_message_list[i].message
+ "</span><span class = \"style-li-whiteboard-date style-fontsize-15-center\">" + timestamp2time(global_whiteboard_message_list[i].creat_time)
+ "</span></li><hr class = \"style-hr-full\">";
}
$(".js-ul-whiteboard-message-list").append(text);
}
function timestamp2time(timestamp){
var stamp = parseInt(timestamp * 1000);//php時間戳只有十位,擴展爲13位
var date = new Date(stamp);
var Y = date.getFullYear() + '-';
var M = (date.getMonth()+1 < 10 ? '0'+(date.getMonth()+1) : date.getMonth()+1) + '-';
var D = (date.getDate() < 10 ? '0' + (date.getDate()) : date.getDate()) + ' ';
var h = (date.getHours() < 10 ? '0' + date.getHours() : date.getHours()) + ':';
var m = (date.getMinutes() <10 ? '0' + date.getMinutes() : date.getMinutes()) + ':';
var s = (date.getSeconds() <10 ? '0' + date.getSeconds() : date.getSeconds());
return Y+M+D+h+m+s;
}
3、服務器端:支持向數據庫內寫入新留言
write2board.php
<?php
session_start();
$message = $_POST['message'];
$author = $_POST['author'];
$author_id = $_POST['author_id'];
$conn = mysqli_connect("localhost","root","","Learn") or die("連接失敗");
mysqli_query($conn,"set names utf8");
$time = time();
$var = mysqli_query($conn,"insert into whiteboard_messages(message,author,author_id,creat_time)values('$message','$author','$author_id','$time')");
echo 'white2board success';
?>
4、網頁端:添加新留言
jscript 核心代碼:
$(".js-button-whiteboard-submit").click(function(){
if ($('.js-whiteboard-textarea-input').val().trim().length ==0) return;
var sendData = {"message":$('.js-whiteboard-textarea-input').val(),"author_id":global_user_info.id,"author":global_user_info.username};//global_user_info 用戶登錄時保存的信息
$.ajax({
url:"http://www.xxx.cn/php/write2board.php",
type:"POST",
data:sendData,
success:function(data){
console.log(data);
if (data == "white2board success")
{
$(".js-whiteboard-textarea-input").val("white2board success");
}
else
{
$(".js-whiteboard-textarea-input").val("white2board failed");
}
},
error:function(xhr){alert("錯誤提示: " + xhr.status + " " + xhr.statusText);}
});
});
5、菜單功能:上一頁、下一頁 翻頁
點擊“上一頁”或“下一頁”時,翻頁顯示所有留言。每頁最多顯示兩條,按照時間降序排列。
顯示第一頁時,隱藏“上一頁”;顯示最後一頁時,隱藏“下一頁”;留言只有一頁時,隱藏“上一頁”和“下一頁”。
jscript代碼:1)在第2條功能已有代碼上修改,藍色爲新增代碼
$(".js-whiteboard-up-page").click(function(){updateWhiteboardMessages("up");});
$(".js-whiteboard-down-page").click(function(){updateWhiteboardMessages("down");});
$(".js-whiteboard-down-page").attr("style","visibility:hidden;");
$(".js-whiteboard-up-page").attr("style","visibility:hidden;");
$.ajax({
url:"http://www.xxx.cn/php/getBoardmessages.php",
type:"POST",
async: false,//設置爲同步操作就可以給全局變量賦值成功
data:{"info":"get_message","offset":0},
success:function(data){
//$(".debug_info").text(data);
console.log(data);
if (data == "no message")
{
$(".js-div-whiteboard-empty-hint").attr("style","display:block;");
$(".js-div-whiteboard-messages").attr("style","display:none;");
return;
}
$(".js-div-whiteboard-empty-hint").attr("style","display:none;");
$(".js-div-whiteboard-messages").attr("style","display:block;");
var info = JSON.parse(data);
global_whiteboard_message_list = info;
/*不止一頁*/
if (global_whiteboard_message_list.length == global_whiteboard_message_limit)
{
$(".js-whiteboard-down-page").attr("style","visibility:visible;");
}
displayWhiteboardMessageList();
},
error:function(xhr){alert("錯誤提示: " + xhr.status + " " + xhr.statusText);}
});
2)
function updateWhiteboardMessages(action)
{
if (action == "up")
{
global_whiteboard_message_offset = global_whiteboard_message_offset - 2;
$(".js-whiteboard-down-page").attr("style","visibility:visible;");
}
else if (action == "down")
{
global_whiteboard_message_offset = global_whiteboard_message_offset + 2;
$(".js-whiteboard-up-page").attr("style","visibility:visible;");
}
else
{
;
}
$.ajax({
url:"http://www.xxx.cn/php/getBoardmessages.php",
type:"POST",
async: false,//設置爲同步操作就可以給全局變量賦值成功
data:{"info":"get_message","offset":global_whiteboard_message_offset},
success:function(data){
console.log(data);
if (data == "no message")
{
if (action == "up")/*已經到第一頁*/
{
$(".js-whiteboard-up-page").attr("style","visibility:hidden;");
global_whiteboard_message_offset = global_whiteboard_message_offset + 2;
}
if (action == "down")/*已經到最後一頁*/
{
$(".js-whiteboard-down-page").attr("style","visibility:hidden;");
global_whiteboard_message_offset = global_whiteboard_message_offset - 2;
}
return;
}
var info = JSON.parse(data);
global_whiteboard_message_list = info;
/*已經到最後一頁*/
if (global_whiteboard_message_list.length < 2)
{
$(".js-whiteboard-down-page").attr("style","visibility:hidden;");
}
/*已經到第一頁*/
if (global_whiteboard_message_offset == 0)
{
$(".js-whiteboard-up-page").attr("style","visibility:hidden;");
}
displayWhiteboardMessageList();
},
error:function(xhr){alert("錯誤提示: " + xhr.status + " " + xhr.statusText);}
});
}
到此代碼功能實現。
上傳網頁及相關代碼到服務器上,體驗一下簡單的留言版功能吧。