php+ajax实现文章自动保存的方法

if(sec>0) {
?????? autosavetimer = setTimeout("autosavetime("+sec+"-1)",1000);　　
???? //这里就是如果当sec>0的时候,第一秒执行一次autosavetime这个函数,同时会把sec-1的值写入autosavetimebox中
}else {
????????? var title=document.getElementById('title');
????????? if(title.value!=''){
????????????????????????????????? autosave_post();
????????? }else{
???????????????? document.getElementById('autosavetimebox').innerHTML='不用保存';???
????????? }
}

var userAgent = navigator.userAgent.toLowerCase();
var is_opera? = (userAgent.indexOf('opera') != -1);
var is_saf??? = ((userAgent.indexOf('applewebkit') != -1) || (navigator.vendor == 'Apple Computer,Inc.'));
var is_webtv? = (userAgent.indexOf('webtv') != -1);
var is_ie???? = ((userAgent.indexOf('msie') != -1) && (!is_opera) && (!is_saf) && (!is_webtv));
var is_ie4??? = ((is_ie) && (userAgent.indexOf('msie 4.') != -1));
var is_moz??? = ((navigator.product == 'Gecko') && (!is_saf));
var is_kon??? = (userAgent.indexOf('konqueror') != -1);
var is_ns???? = ((userAgent.indexOf('compatible') == -1) && (userAgent.indexOf('mozilla') != -1) && (!is_opera) && (!is_webtv) && (!is_saf));
var is_ns4??? = ((is_ns) && (parseInt(navigator.appVersion) == 4));
var is_mac??? = (userAgent.indexOf('mac') != -1);
if ((is_ie & !is_ie4) || is_moz || is_saf || is_opera)
{
??? var allowajax=1;
}else{
??? var allowajax=0;
}
var xmlHttp = false;
function makeSendData(postData,url,functionName,httptype) {
?
var posturl=url;
try {
?? xmlHttp = new ActiveXObject("Msxml2.XMLHTTP");
} catch (e) {
?? try {
???? xmlHttp = new ActiveXObject("Microsoft.XMLHTTP");
?? } catch (e2) {
???? xmlHttp = false;
?? }
}
if (!xmlHttp && typeof XMLHttpRequest != 'undefined') {
?? xmlHttp = new XMLHttpRequest();
}
?
if (!xmlHttp) {
??????? alert('Cannot send an XMLHTTP request');
??????? return false;
}
?
// 提交表单的方式
xmlHttp.open(httptype,posturl,true);
?
// 当表单提交完成后触发一个事件
var changefunc="xmlHttp.onreadystatechange = "+functionName;? ///////from bob
eval (changefunc);
xmlHttp.setRequestHeader('Content-Type','application/x-www-form-urlencoded');?
xmlHttp.send(postData);
}
function autosave_post()
{
??? var title=document.getElementById('title').value;
??? var content = window.frames["Editor"].window.frames["HtmlEditor"].document.getElementsByTagName("BODY")[0].innerHTML;
??? var postTime=document.getElementById('postTime').value;
??? if(allowajax==1)
??? {
??????? content=postencode(content);
??????? title=postencode(title);
??????? var post="title="+title+"&content="+content+"&postTime="+postTime+"";
??????? var url="ajax.php?act=autosave";
??????? makeSendData(post,'autosave','POST');
??? }
}
function autosave()
{
??? if(xmlHttp.readyState == 4)
??? {
??????? if(xmlHttp.status == 200)
??????? {
??????????? var autoresponse=xmlHttp.responseText;
??????????? var automessage=document.getElementById('autosavetimebox');
??????????? if(autoresponse.indexOf("<autosave_error>")!=-1)
??????????? {
??????????????? automessage.innerHTML='您还没有添写信息,不用保存草稿';
??????????????? return false;
??????????? }
??????????? if(autoresponse.indexOf("<autosave_ok>")!=-1)
??????????? {
??????????????? automessage.innerHTML='保存成功,您可以在发生意外的时候载入草稿';
??????????????? finddraft();
??????????? }
??????? }
??? }
}
function finddraft()
{
??? if(allowajax==1)
??? {
??????? var url="ajax.php?act=loaddraft";
??????? makeSendData(null,'loaddraft','POST');
??? }
}
function loaddraft()
{
??? var draftbox=document.getElementById('draft');
??? if(xmlHttp.readyState < 4)
??? {
??????? draftbox.innerHTML='草稿载入中...';
??? }
??? if(xmlHttp.readyState == 4)
??? {
??????? if(xmlHttp.status == 200)
??????? {
??????????? draftbox.innerHTML=xmlHttp.responseText;
??????? }
??? }
}
function cleardraft()
{
??? if(allowajax==1)
??? {
??????? var url="ajax.php?act=cleardraft";
??????? makeSendData(null,'nodraft','POST');
??? }
}
function nodraft()
{
??? var draftbox=document.getElementById('draft');
??? if(xmlHttp.readyState < 4)
??? {
??????? draftbox.innerHTML='载入中...';
??? }
??? if(xmlHttp.readyState == 4)
??? {
??????? if(xmlHttp.status == 200)
??????? {
??????????? draftbox.innerHTML=xmlHttp.responseText;
??????? }
??? }
}
//encode string
function postencode (str) {?
??? str=encodeURIComponent(str);
??? if (is_moz) str=str.replace(/%0A/g,"%0D%0A"); //from bob
??? return str;
}

var autosavetimer;
function autosavetime(sec) {
?? clearTimeout(autosavetimer);
?? document.getElementById('autosavetimebox').innerHTML=sec+"秒";
?? if(sec>0) {
?????? autosavetimer = setTimeout("autosavetime("+sec+"-1)",1000);
?? }else {
?????? var blogtitle=document.getElementById('title');
?????? if(blogtitle.value!=''){
?????????? autosave_post();
?????? }else{
?????????? document.getElementById('autosavetimebox').innerHTML='不用保存';??
?????? }
?? }
}
function startimer()
{
??? var starttime=document.getElementById('autosavetimebox').innerHTML;
??? if(starttime=='保存成功,您可以在发生意外的时候载入草稿' || starttime=='您还没有添写信息,不用保存草稿')
??? {
??????? starttime='60';
??? }else{
??????? starttime=starttime.replace('秒','');
??? }
??? var autosavefunbox=document.getElementById('autosavefunbox');
??? autosavefunbox.innerHTML='<a href="javascript教程:" onClick="javascript：stoptimer()">停止计时</a>';
??? starttime==0 ? starttime=60 : starttime=starttime;
??? autosavetime(starttime);
}
function stoptimer()
{
??? var autosavefunbox=document.getElementById('autosavefunbox');
??? autosavefunbox.innerHTML='<a href="javascript：" onClick="javascript：startimer()">开始计时</a>';
??? clearTimeout(autosavetimer);
}