Chris's wiki | Main / CookieHandling

This is some HTML that saves a user name and a background colour preference between sessions

<html>
<head>
<title>Cookies Example</title>
<style type="text/css">
<!--
.red {
        background:#ffbbbb;
}

.blue {
        background:#bbbbff;
}
-->
</style>

<script type="text/javascript" src="cookies.js"></script>

<script language="javascript">
function changeStyle(pref_style){
        document.getElementById('body').className=pref_style;
        setCookie("prefstyle", pref_style);
}

function setPrefs(){
        var pref_style = getCookie("prefstyle");
        document.getElementById('body').className=pref_style;
        sayHello();
}

function storeUserName(){
        var username = document.getElementById('username').value;
        alert(username);
        setCookie("username", username);
        sayHello();
}

function sayHello(){
        if(getCookie("username") != null) {
                document.getElementById('getUserName').style.visibility="hidden";
                document.getElementById('sayHello').style.visibility="visible";
                document.getElementById('sayHello').innerHTML="Hello " + getCookie("username");
        }
}


</script>

</head>
<body id="body" onload='setPrefs();'>

<div id='getUserName'>
<form onsubmit='storeUserName()'>
Hello, what is you name? <input id='username' /><input type='submit' value='Set' />
</form>
</div>

<div id='sayHello' style="visibility: hidden;">
Hello
</div>

<a href='javascript:changeStyle("blue")'>I like blue</a>
<br>
<a href='javascript:changeStyle("red")'>I like red</a>
<P>
<a href="#" onclick='alert(getCookie("prefstyle"));return false'>Get Cookie!</a>&nbsp;
<a href="#" onclick='deleteCookie("prefstyle");deleteCookie("username");return false'>Delete Cookies!</a>

</body>
</html>

The content of the cookies.js is

/**
* Sets a Cookie with the given name and value.
*
* name       Name of the cookie
* value      Value of the cookie
* [expires]  Expiration date of the cookie (default: end of current session)
* [path]     Path where the cookie is valid (default: path of calling document)
* [domain]   Domain where the cookie is valid
*              (default: domain of calling document)
* [secure]   Boolean value indicating if the cookie transmission requires a
*              secure transmission
*/
function setCookie(name, value) {
        var largeExpDate = new Date ();
        largeExpDate.setTime(largeExpDate.getTime() + (30 * 24 * 3600 * 1000));
        var curCookie = name + "=" + escape(value) + "; expires=" + largeExpDate.toGMTString();
        document.cookie = curCookie;
}

/*
name - name of the desired cookie
return string containing value of specified cookie or null
if cookie does not exist
*/

function getCookie(name) {
        var dc = document.cookie;
        var prefix = name + "=";
        var begin = dc.indexOf("; " + prefix);
        if (begin == -1) {
                begin = dc.indexOf(prefix);
                if (begin != 0) return null;
        } else
        begin += 2;
        var end = document.cookie.indexOf(";", begin);
        if (end == -1)
        end = dc.length;
        return unescape(dc.substring(begin + prefix.length, end));
}


/*
name - name of the cookie
[path] - path of the cookie (must be same as path used to create cookie)
[domain] - domain of the cookie (must be same as domain used to
create cookie)
path and domain default if assigned null or omitted if no explicit
argument proceeds
*/

function deleteCookie(name, path, domain) {
        if (getCookie(name)) {
                document.cookie = name + "=" +
                ((path) ? "; path=" + path : "") +
                ((domain) ? "; domain=" + domain : "") +
                "; expires=Thu, 01-Jan-70 00:00:01 GMT";
        }
}

// date - any instance of the Date object
// * hand all instances of the Date object to this function for "repairs"

function fixDate(date) {
        var base = new Date(0);
        var skew = base.getTime();
        if (skew > 0)
        date.setTime(date.getTime() - skew);
}

Main.SideBar (edit)

CookieHandling