Code to determine whether the user is online_javascript skills

Consider two situations: (1) The user closes the browser or is redirected to other web pages

Copy the code The code is as follows: function exit_init() { if(xmlhttp.readyState==4){ if(xmlhttp.status==200 ){ // } else{ alert("there was a problem accessing the server:" xmlhttp.status); } } } // Define the onbeforeunload event of windows. When the user exits abnormally, that is, the browser is closed abnormally, the user login status is processed window.onbeforeunload=function () { //if(event.clientY exit_request = false; //Create request object if (window.XMLHttpRequest) { exit_request = new XMLHttpRequest(); if (exit_request.overrideMimeType){ exit_request.overrideMimeType('text/xml'); } } else if (window.ActiveXObject) { try{ exit_request = new ActiveXObject("Msxml2.XMLHTTP"); } catch (e) { try { exit_request = new ActiveXObject("Microsoft.XMLHTTP"); } catch (e) { } } } if (!exit_request) { alert("Your brower is not compatible with the current opration. Please use the IE 5.0! "); return false; } var url=' null.php?userid=' document.getElementById("userid").value; //Define the method exit_init called by the page, not exit_init(); no(); exit_request.onreadystatechange = exit_init; exit_request.open('GET', url, true); //Disable IE caching exit_request.setRequestHeader("If-Modified-Since", "0"); //Send data exit_request.send(null); } //} Explanation: null.php is used to set the user status to offline (2) The user no longer browses this website for a long time Idea: Create a table active_stat with attributes including userid, lasttime, and nowtime. Every time the user opens this website, change lasttime to the current time now(), change nowtime to the current time every 1 minute, and determine whether nowtime-lasttime is greater than 20 minutes. If it is greater, modify the user status to offline Copy code The code is as follows: function test(userid){ setInterval("offline('" userid "')", 60000 ); //Execute every 1 minute } function offline(userid){ var xmlhttp=false; try{ xmlhttp=new activeXObject('Msxml2.XMLHTTP'); }catch(e){ try{ xmlhttp=new ActiveXObject('Microsoft.XMLHTTP'); } catch(e){ try{ xmlhttp=new XMLHttpRequest(); }catch(e){} } } if(xmlhttp.readyState==4| |xmlhttp.readyState==0) { xmlhttp.open('get','../user/include/offline.php?userid=' userid,false); xmlhttp.onreadystatechange= function(){ if(xmlhttp.readyState==4){ if(xmlhttp.status==200){ // } else{ alert("there was a problem accessing the server:" ;BODY onLoad="test(' ');">

offline.php

Copy the code

The code is as follows: //Connect to the database $userid=$_GET["userid"]; pg_exec("update active_stat set nowtime=now() where userid='".$userid."';"); $result=pg_exec($dbconn,"select (nowtime-lasttime) as activetime from active_stat where userid='".$userid."'"); $str=pg_result($result,0,"activetime"); if(strlen($str)>16){ $array=explode(" ",$str); $t=explode(":",$array[1]); $t[0]=$t[0] $array[0] *24; $s=explode(".",$t[2]); $t[2]=$s[0]; $y=((int)$t[ 0])*3600 ((int)$t[1])*60 ((int)$t[2]); } else{ $total_time=explode(".",$ str); $x=explode(":",$total_time[0]); $y=((int)$x[0])*3600 ((int)$x[1]) *60 ((int)$x[2]); } if($y>=1200){ pg_exec("update users set status='f' where userid='".$ userid."';"); } ?>