发布三个ajax相关的函数，包括无刷新提交表单等

几个月前，因为项目需求，我写了下面的三个ajax相关的函数。发布出来和大家分享。
第一个是用来无刷新加载一段HTML
第二个是把表单数据转换成一串请求字符串
第三个是结合函数一和函数二的无刷新提交表单实现。

还有一点要提到的是，无刷新表单提交，还不能对文件上传进行处理，这个主要是因为浏览器的安全设置。目前无刷新的上传，一般是用iframe来实现的。关于这个，我们在google里搜索能找到很多。

网上虽然已经有很多优秀的ajax的类和函数了，但是或许我这几个函数对大家还有点用处，于是我就发布出来了。
可以在这里下载。

//@desc    load a page(some html) via xmlhttp,and display on a container 
//@param   url          the url of the page will load,such as "index.php" 
//@param   request      request string to be sent,such as "action=1&name=surfchen" 
//@param   method       POST or GET 
//@param   container          the container object,the loaded page will display in container.innerHTML 
//@usage  
//         ajaxLoadPage('index.php','action=1&name=surfchen','POST',document.getElementById('my_home')) 
//         suppose there is a html element of "my_home" id,such as "<span id='my_home'></span>"  
//@author  SurfChen <surfchen@gmail.com> 
//@url     http://www.surfchen.org/ 
//@license http://www.gnu.org/licenses/gpl.html GPL 
function ajaxLoadPage(url,request,method,container) 
{ 
    method=method.toUpperCase(); 
    var loading_msg='Loading...';//the text shows on the container on loading. 
    var loader=new XMLHttpRequest;//require Cross-Browser XMLHttpRequest 
    if (method=='GET') 
    { 
        urls=url.split("?"); 
        if (urls[1]=='' || typeof urls[1]=='undefined') 
        { 
            url=urls[0]+"?"+request; 
        } 
        else 
        { 
            url=urls[0]+"?"+urls[1]+"&"+request; 
        } 

        request=null;//for GET method,loader should send NULL 
    } 
    loader.open(method,url,true); 
    if (method=="POST") 
    { 
        loader.setRequestHeader("Content-Type","application/x-www-form-urlencoded"); 
    } 
    loader.onreadystatechange=function(){ 
        if (loader.readyState==1) 
        { 
            container.innerHTML=loading_msg; 

        } 
        if (loader.readyState==4) 
        { 
            container.innerHTML=loader.responseText; 
        } 
    } 
    loader.send(request); 
} 
//@desc    transform the elements of a form object and their values into request string( such as "action=1&name=surfchen") 
//@param   form_obj          the form object 
//@usage   formToRequestString(document.form1) 
//@notice  this function can not be used to upload a file.if there is a file input element,the func will take it as a text input. 
//         as I know,because of the security,in most of the browsers,we can not upload a file via xmlhttp. 
//         a solution is iframe. 
//@author  SurfChen <surfchen@gmail.com> 
//@url     http://www.surfchen.org/ 
//@license http://www.gnu.org/licenses/gpl.html GPL 
function formToRequestString(form_obj) 
{ 
    var query_string=''; 
    var and=''; 
    //alert(form_obj.length); 
    for (i=0;i<form_obj.length ;i++ ) 
    { 
        e=form_obj[i]; 
        if (e.name!='') 
        { 
            if (e.type=='select-one') 
            { 
                element_value=e.options[e.selectedIndex].value; 
            } 
            else if (e.type=='checkbox' || e.type=='radio') 
            { 
                if (e.checked==false) 
                { 
                    break;     
                } 
                element_value=e.value; 
            } 
            else 
            { 
                element_value=e.value; 
            } 
            query_string+=and+e.name+'='+element_value.replace(/\&/g,"%26"); 
            and="&" 
        } 

    } 
    return query_string; 
} 
//@desc    no refresh submit(ajax) by using ajaxLoadPage and formToRequestString 
//@param   form_obj          the form object 
//@param   container          the container object,the loaded page will display in container.innerHTML 
//@usage   ajaxFormSubmit(document.form1,document.getElementById('my_home')) 
//@author  SurfChen <surfchen@gmail.com> 
//@url     http://www.surfchen.org/ 
//@license http://www.gnu.org/licenses/gpl.html GPL 
function ajaxFormSubmit(form_obj,container) 
{ 
    ajaxLoadPage(form_obj.getAttributeNode("action").value,formToRequestString(form_obj),form_obj.method,container) 
}