php+mysql结合Ajax实现点赞功能完整实例_php技巧

<span>0</span>
<button onclick="goodplus(1);">good+1</button>

<span>0</span>
<button onclick="goodplus(2);">good+1</button>

<span>0</span>
<button onclick="goodplus(3);">good+1</button>

<span>0</span>
<button onclick="goodplus(4);">good+1</button>

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！")  
  } 
}

for(var i = 1; i < span.length + 1; i++){ 
  senddata(i);  
}

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(); 
} 

//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()) 
}

<&#63;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)
&#63;>

<span>0</span>
<button onclick="goodplus(1);">good+1</button>

<span>0</span>
<button onclick="goodplus(2);">good+1</button>

<span>0</span>
<button onclick="goodplus(3);">good+1</button>

<span>0</span>
<button onclick="goodplus(4);">good+1</button>