要实现点赞功能,有多种实现方式,这里总结一下利用Ajax,php和mysql来实现点赞的数据的功能。具体步骤如下:
一、页面中的HTML代码部分:
<span>0</span> <button>good+1</button> <span>0</span> <button>good+1</button> <span>0</span> <button>good+1</button> <span>0</span> <button>good+1</button>
二、写javascript
1、实现上面的button的点击事件goodplus
var span = document.getElementsByTagName('span');//获取存放点赞数的dom var num; //点赞数 var flag = 0; //不同情况的标记 function goodplus(gindex){ flag = 1; num = parseInt(span.item(gindex-1).innerHTML); if(checkcookie(gindex) == true){ num = num + 1; senddata(gindex); //通过Ajax修改页面上的数据 }else{ alert("你已经点过赞咯!") } }
2、页面一打开时就应该更新点赞数据
for(var i = 1; i < span.length + 1; i++){ senddata(i); }
3、通过Ajax获取数据senddata函数
function senddata(aindex){ var xmlhttp; var txt; if(window.XMLHttpRequest){ xmlhttp=new XMLHttpRequest(); }else{ xmlhttp=new ActiveXObject("Microsoft.XMLHTTP"); } xmlhttp.onreadystatechange=function(){ if(xmlhttp.readyState == 4 && xmlhttp.status == 200){ txt = xmlhttp.responseText; //获取返回的数据 var cookieindex = aindex - 1; document.getElementsByTagName('span').item(cookieindex).innerHTML = txt; //赋值 } } xmlhttp.open("GET","路径/index.php?num=" + num + '&flag=' + flag + '&aindex=' + aindex,true); xmlhttp.send(); }
4、通过设置cookie来判断是否已经点赞,如果有cookie则提示已经点赞,如果没有cookie则允许点赞,而且会设置cookie
//判断是否已经存在了cookie function checkcookie(gindex){ var thiscookie = 'goodplus' + gindex; var mapcookie = getCookie(thiscookie) if (mapcookie!=null && mapcookie!=""){ return false; }else { setCookie(thiscookie,thiscookie,365); return true; } } //获取cookie function getCookie(c_name){//获取cookie,参数是名称。 if (document.cookie.length > 0){//当cookie不为空的时候就开始查找名称 c_start = document.cookie.indexOf(c_name + "="); if (c_start != -1){ //如果开始的位置不为-1就是找到了、找到了之后就要确定结束的位置 c_start = c_start + c_name.length + 1 ; //cookie的值存在名称和等号的后面,所以内容的开始位置应该是加上长度和1 c_end = document.cookie.indexOf(";" , c_start); if (c_end == -1) { c_end = document.cookie.length; } return unescape(document.cookie.substring(c_start , c_end));//返回内容,解码。 } } return ""; } //设置cookie function setCookie(c_name,value,expiredays){ //存入名称,值,有效期。有效期到期事件是今天+有效天数。然后存储cookie, var exdate=new Date(); exdate.setDate( exdate.getDate() + expiredays ) document.cookie = c_name + "=" + escape(value) + ((expiredays==null) ? "" : "; expires=" + exdate.toGMTString()) }
三、index.php页面:
<?php $num = $_GET['num']; $aindex = $_GET['aindex']; $con = mysql_connect("localhost","root",""); if (!$con){ die('Could not connect: ' . mysql_error()); } mysql_select_db("goodplus", $con); $sql0s = "SELECT * FROM `good` where `id` = ".$aindex; $sql0 = mysql_query($sql0s); if($_GET['flag'] == 0){ while($row = mysql_fetch_array($sql0)){ echo $row['value']; } }else if($_GET['flag'] == 1){ $sql="UPDATE `goodplus`.`good` SET `value` = '".$num."' WHERE `good`.`id` = ".$aindex; if (!mysql_query($sql,$con)){ die('Error: ' . mysql_error()); } echo $num; } mysql_close($con) ?>
四、最终的index.html页面如下:
<!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=gb2312" /> <title>无标题文档</title> </head> <body> <span>0</span> <button>good+1</button> <span>0</span> <button>good+1</button> <span>0</span> <button>good+1</button> <span>0</span> <button>good+1</button> <script type="text/javascript"> var span = document.getElementsByTagName('span'); var num; var flag = 0; for(var i = 1; i < span.length + 1; i++){ senddata(i); } function goodplus(gindex){ flag = 1; num = parseInt(span.item(gindex-1).innerHTML); if(checkcookie(gindex) == true){ num = num + 1; senddata(gindex); }else{ alert("你已经点过赞咯!") } } function senddata(aindex){ var xmlhttp; var txt; if(window.XMLHttpRequest){ xmlhttp=new XMLHttpRequest(); }else{ xmlhttp=new ActiveXObject("Microsoft.XMLHTTP"); } xmlhttp.onreadystatechange=function(){ if(xmlhttp.readyState == 4 && xmlhttp.status == 200){ txt = xmlhttp.responseText; var cookieindex = aindex - 1; document.getElementsByTagName('span').item(cookieindex).innerHTML = txt; } } xmlhttp.open("GET","/ajax/json/index.php?num=" + num + '&flag=' + flag + '&aindex=' + aindex,true); xmlhttp.send(); } //判断是否已经存在了cookie function checkcookie(gindex){ var thiscookie = 'sdcity_foodmap_goodplus' + gindex; var mapcookie = getCookie(thiscookie) if (mapcookie!=null && mapcookie!=""){ return false; }else { setCookie(thiscookie,thiscookie,365); return true; } } //获取cookie function getCookie(c_name){ //获取cookie,参数是名称。 if (document.cookie.length > 0){ //当cookie不为空的时候就开始查找名称 c_start = document.cookie.indexOf(c_name + "="); if (c_start != -1){ //如果开始的位置不为-1就是找到了、找到了之后就要确定结束的位置 c_start = c_start + c_name.length + 1 ; //cookie的值存在名称和等号的后面,所以内容的开始位置应该是加上长度和1 c_end = document.cookie.indexOf(";" , c_start); if (c_end == -1) { c_end = document.cookie.length; } return unescape(document.cookie.substring(c_start , c_end));//返回内容,解码。 } } return ""; } //设置cookie function setCookie(c_name,value,expiredays){ //存入名称,值,有效期。有效期到期事件是今天+有效天数。然后存储cookie, var exdate=new Date(); exdate.setDate( exdate.getDate() + expiredays ) document.cookie = c_name + "=" + escape(value) + ((expiredays==null) ? "" : "; expires=" + exdate.toGMTString()) } </script> </body> </html>