Php+mysql combined with Ajax to achieve a complete example of point-praise function _php Skills

The example of this article describes the method of Php+mysql combining Ajax to realize the point-praise function. Share to everyone for your reference. Specifically as follows:

To achieve the point of praise function, there are a variety of ways to achieve, here summed up the use of ajax,php and MySQL to achieve the point of praise of the data function. The specific steps are as follows:

Part of the HTML code in the page:

<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>

Second, write JavaScript

1, to achieve the button above the Click event Goodplus

var span = document.getElementsByTagName (' span ');//Get the DOM Var num that holds the point of Praise 
 ;//Dot count 
 var flag = 0;//Mark 
  
 of different circumstances function Goodplus (gindex) { 
  flag = 1; 
  num = parseint (Span.item (gindex-1). InnerHTML); 
  if (Checkcookie (gindex) = = true) { 
   num = num + 1; 
   SendData (Gindex); Modify the data on the page with Ajax 
  }else{ 
   alert ("You've been lit!") ")  
  } 
}

2. When the page is opened, you should update the point of praise data

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

3. Get data SendData function via Ajax

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 =) { 
    txt = Xmlhttp.responsetext; Gets the returned data 
    var cookieindex = aindex-1; 
    document.getElementsByTagName (' span '). Item (cookieindex). InnerHTML = txt; Assignment 
   } 
  Xmlhttp.open ("Get", "path/index.php?num=" + num + ' &flag= ' + flag + ' &aindex= ' + Aindex, true); 
  Xmlhttp.send (); 
} 

4, by setting a cookie to determine whether it has been a point of praise, if there is a cookie tip has been point of praise, if no cookie is allowed to point praise, and will set cookies

To determine if there is already a 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; 
  }//Get Cookie function GetCookie (c_name) {//Get cookie, parameter is name. 
   if (Document.cookie.length > 0) {//When the cookie is not empty, start looking for the name C_start = document.cookie.indexOf (c_name + "=");
 if (C_start!=-1) {//If the starting position is not-1 is found, found and then determine the end of the position C_start = C_start + c_name.length + 1; 
    The value of the cookie exists after the name and the equal sign, so the start position of the content should be plus length and 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));//content, decoding. 
} return ""; //Set Cookie function Setcookie (c_name,value,expiredays) {//Deposit name, value, validity period. Expiration event is today + valid days. 
  Then store cookies, var exdate=new Date (); Exdate.setdate (exdate.getdate () + expireDays) Document.cookie = c_name + "=" + Escape (value) + ((expiredays==null)? "" : ";

 Expires= "+ exdate.togmtstring ())}

Third, index.php page:

<?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);

$sql 0s = "select * from" good ' where ' id ' = '. $aindex;
$sql 0 = mysql_query ($sql 0s);

if ($_get[' flag '] = = 0) {while
 ($row = mysql_fetch_array ($sql 0)) {
 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)
?>

Four, the final index.html page is as follows:

<! DOCTYPE HTML PUBLIC "-//W3C//DTD XHTML 1.0 transitional//en" "Http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd ">