Using Cookies With JavaScript - Speaking Native (
Page 6 of 7 )
So that takes care of writing cookies, and then reading the values back. Now, how about a composite example that you can actually use?
In this next example, I'll assume a multi-lingual Web site, where the user has a choice of viewing the content in either French or English. The first time the user visits the site, (s)he is permitted to select one of the two languages. This choice is stored in a cookie, so that on the next visit, the client is automatically redirected to the chosen language without requiring the user to re-select a language.
<html>
<head>
<script language="JavaScript" src="cookieLibrary.js"></script>
<script language="JavaScript">
// check to see if cookie exists
// if yes, redirect to language page
if (GetCookie("lang") == "EN")
{
document.location.href="index.en.html";
}
else if (GetCookie("lang") == "FR")
{
document.location.href="index.fr.html";
}
// function to write selected language to cookie
function lang(l)
{
// set expiry date for 1 year from now
var d = new Date();
d.setDate(d.getDate() + 365);
// write cookie
SetCookie("lang", l, d);
// take user to appropriate language page
if (l == "EN")
{
document.location.href="index.en.html";
}
else if (l == "FR")
{
document.location.href="index.fr.html";
}
}
</script>
</head>
<body>
<h2>
Please select your language:
<ul>
<li><a href="javascript:lang('EN');">English</a>
<li><a href="javascript:lang('FR');">French</a>
</ul>
</h2>
</body>
</html>
That was simple enough. When the user visits the page, the code first checks to see if a cookie with the selected language already exists. If it does, the browser is automatically redirected to pages in that language. If no cookie exists, it implies that the user has not selected a language, and so a language choice is displayed. The language selected is then written to a cookie in preparation for the next visit.
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