![• function setCookie(cname, cvalue, exdays) {
var d = new Date();
d.setTime(d.getTime() + (exdays*24*60*60*1000));
var expires = "expires="+d.toUTCString();
document.cookie = cname + "=" + cvalue + "; " + expires;
}
function getCookie(cname) {
var name = cname + "=";
var ca = document.cookie.split(';');
for(var i=0; i<ca.length; i++) {
var c = ca[i];
while (c.charAt(0)==' ') c = c.substring(1);
if (c.indexOf(name) == 0) return c.substring(name.length, c.length);
}
return "";
}
function checkCookie() {
var user = getCookie("username");
if (user != "") {
alert("Welcome again " + user);
} else {
user = prompt("Please enter your name:", "");
if (user != "" && user != null) {
setCookie("username", user, 365);
}
}
}](https://image.slidesharecdn.com/cookies-150913063128-lva1-app6891/85/java-Cookies-10-320.jpg)
![A Function to Get a Cookie
• function getCookie(cname) {
var name = cname + "=";
var ca = document.cookie.split(';');
for(var i=0; i<ca.length; i++) {
var c = ca[i];
while (c.charAt(0)==' ') c = c.substring(1);
if (c.indexOf(name) == 0) return
c.substring(name.length,c.length);
}
return "";
}](https://image.slidesharecdn.com/cookies-150913063128-lva1-app6891/85/java-Cookies-12-320.jpg)
java Cookies
- 2. Contents • What’s a Cookie! • Types of Cookie • Cookie parameters • JavaScript Cookie • Creating a Cookie • Reading, Changing and Deleting a Cookie • The Cookie string • Set a Cookie • Get a Cookie • Check a Cookie
- 3. What’s a Cookie! • It is a file residing on your web browser • Stores user info from a website • Updated via HTML • Queried via JavaScript
- 4. Types of Cookie • Session cookie • Persistent cookie • Malicious cookie
- 5. Cookie parameters • The name of the cookie • The value of the cookie • The expiration date of the cookie • The path the cookie is valid for • The domain the cookie is valid for • The need for a secure connection
- 6. JavaScript Cookie • Initially a visitor fills in his name • Name is saved • Welcome message is displayed at his next visit • A JavaScript can create, delete and read cookies • A JavaScript program checks the cookie file • It queries the user – E.g.: username=“John Doe”;
- 7. Create a Cookie – document.cookie="username=John Doe"; • Expiry date: – document.cookie="username=John Doe; expires=Thu, 18 Dec 2013 12:00:00 UTC"; • Cookie path: – document.cookie="username=John Doe; expires=Thu, 18 Dec 2013 12:00:00 UTC; path=/";
- 8. Reading , Changing and Deleting a Cookie • Read: – var x = document.cookie; • Change: – document.cookie="username=John Doe"; – document.cookie="username=John Smith; expires=Thu, 18 Dec 2013 12:00:00 UTC; path=/"; • Delete: – document.cookie = "username=; expires=Thu, 01 Jan 1970 00:00:00 UTC";
- 9. The Cookie String – Document.cookie=cookie1,cookie2…….. • New cookies are created over and over • Cookie1=value; cookie2=value;……..
- 10. • function setCookie(cname, cvalue, exdays) { var d = new Date(); d.setTime(d.getTime() + (exdays*24*60*60*1000)); var expires = "expires="+d.toUTCString(); document.cookie = cname + "=" + cvalue + "; " + expires; } function getCookie(cname) { var name = cname + "="; var ca = document.cookie.split(';'); for(var i=0; i<ca.length; i++) { var c = ca[i]; while (c.charAt(0)==' ') c = c.substring(1); if (c.indexOf(name) == 0) return c.substring(name.length, c.length); } return ""; } function checkCookie() { var user = getCookie("username"); if (user != "") { alert("Welcome again " + user); } else { user = prompt("Please enter your name:", ""); if (user != "" && user != null) { setCookie("username", user, 365); } } }
- 11. A Function to set a Cookie • function setCookie(cname, cvalue, exdays) { var d = new Date(); d.setTime(d.getTime() + (exdays*24*60*60*1000)); var expires = "expires="+d.toUTCString(); document.cookie = cname + "=" + cvalue + "; " + expires; }
- 12. A Function to Get a Cookie • function getCookie(cname) { var name = cname + "="; var ca = document.cookie.split(';'); for(var i=0; i<ca.length; i++) { var c = ca[i]; while (c.charAt(0)==' ') c = c.substring(1); if (c.indexOf(name) == 0) return c.substring(name.length,c.length); } return ""; }
- 13. A Function to Check a Cookie • function checkCookie() { var username=getCookie("username"); if (username!="") { alert("Welcome again " + username); }else{ username = prompt("Please enter your name:", ""); if (username != "" && username != null) { setCookie("username", username, 365); } } }