这里用户第一次访问网页时会提示用户输入一个昵称，然后写入cookie，当用户再次来到时会读取cookie信息，提取用户昵称，欢迎用户的到来
<!DOCTYPE html> <html> <head> <script> function getCookie(c_name) { var c_value = document.cookie; var c_start = c_value.indexOf(" " + c_name + "="); if (c_start == -1) { c_start = c_value.indexOf(c_name + "="); } if (c_start == -1) { c_value = null; } else { c_start = c_value.indexOf("=", c_start) + 1; var c_end = c_value.indexOf(";", c_start); if (c_end == -1) { c_end = c_value.length; } c_value = unescape(c_value.substring(c_start,c_end)); } return c_value; } function setCookie(c_name,value,exdays) { var exdate=new Date(); exdate.setDate(exdate.getDate() + exdays); var c_value=escape(value) + ((exdays==null) ? "" : "; expires="+exdate.toUTCString()); document.cookie=c_name + "=" + c_value; } function checkCookie() { var username=getCookie("username"); if (username!=null && username!="") { alert("Welcome again " + username); } else { username=prompt("Please enter your name:",""); if (username!=null && username!="") { setCookie("username",username,365); } } } </script> </head> <body> </body> </html>