Xajax (any): Tips and Tricks: Detecting Support
Xajax (any): Tips and Tricks: Detecting Support
Here is some html/javascript code you can use to detect whether or not the user's browser supports cookies, javascript, and ajax and then display a message if it doesn't.
Helper functions for detecting cookie and Ajax support:
<script type="text/javascript">
<!--
// Cookie handling
var Cookie =
{
read: function (name)
{
var arrCookies = document.cookie.split ('; ');
for (var i=0; i<arrCookies.length; i++)
{
var arrCookie = arrCookies[i].split ('=');
if (arrCookie[0] == name)
{
return decodeURIComponent (arrCookie[1]);
}
}
return false;
},
write: function (name, value, expires, path)
{
if (expires)
{
var date = new Date ();
date.setTime (date.getTime () + (((((expires * 24) * 60) * 60) * 1000)));
expires = '; expires=' + date.toGMTString ();
}
else expires = '';
if (!path) path = '/';
document.cookie = name+'='+encodeURIComponent (value)+expires+'; path='+path;
},
remove: function (name)
{
this.write (name, '', -1);
}
}
// Detects if can set a cookie in the browser
function browserSupportsCookies()
{
Cookie.write('cookiesEnabled', 1);
var boolCookiesEnabled = Cookie.read('cookiesEnabled');
Cookie.remove('cookiesEnabled');
if (boolCookiesEnabled != 1)
{
return false;
}
return true;
}
// Detects if the browser supports Ajax
function browserSupportsAjax()
{
if (typeof XMLHttpRequest == "undefined" && typeof ActiveXObject == "undefined" && window.createRequest == "undefined")
{
return false;
}
return true
}
// Detects if the browser can use ActiveX if necessary
function ActiveXEnabledOrUnnecessary ()
{
if (typeof ActiveXObject != "undefined")
{
var xhr = null;
try{
xhr=new ActiveXObject("Msxml2.XMLHTTP");
}catch (e){
try{
xhr=new ActiveXObject("Microsoft.XMLHTTP");
}catch (e2){
try{
xhr=new ActiveXObject("Msxml2.XMLHTTP.4.0");
}catch (e3){
xhr=null;
}
}
}
if (xhr == null)
{
return false
}
}
return true;
}
-->
</script>
Display an error message to the user if they don't have the proper support:
<!-- Detect support for cookies and Ajax and display message if not -->
<div id="supportError">
<noscript>
<div>JavaScript appears to be either disabled or unsupported by your browser.
This web application requires JavaScript to function properly.
Please enable JavaScript in your browser settings,
or upgrade to a browser with JavaScript support and try again.</div>
</noscript>
<script type="text/javascript">
<!--
if (!browserSupportsCookies())
{
var msg = '<div>Cookies appear to be either disabled or unsupported by your browser. '
msg += 'This web application requires Cookies to function properly. ';
msg += 'Please enable Cookies in your browser settings ';
msg += 'or upgrade to a browser with Cookie support and try again.</div>'
document.write(msg);
}
if (!browserSupportsAjax())
{
var msg = '<div>Your browser does not appear to support Ajax technology. '
msg += 'This web application requires Ajax to function properly. ';
msg += 'Please upgrade to a browser with Ajax support and try again.</div>';
document.write(msg);
}
if (!ActiveXEnabledOrUnnecessary())
{
var msg = '<div>ActiveX appears to be disabled in your browser. ';
msg += 'This web application requires Ajax technology to function properly. ';
msg += 'In Internet Explorer versions earlier than 7.0, Ajax is implemented using ActiveX. ';
msg += 'Please enable ActiveX in your browser security settings ';
msg += 'or upgrade to a browser with Ajax support and try again.</div>';
document.write(msg);
}
-->
</script>
</div>
