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使用JavaScript设置,读取和写入Cookie

[英]Setting, Reading and Writing Cookie with JavaScript

在此示例中,我要通过提示询问用户的名称,然后使用Cookie将其写入div,“欢迎使用,保存的Cookie!”。 输入之后,然后他们每次在到期前访问该页面。

我得到浏览器提示输入我的名字的提示,然后将其写为“欢迎使用,未定义!”。 我不知道为什么会收到错误消息。

 //Setting cookie for Users Name function set_it() { var userName = prompt("Please Enter Your Name", ""), thetext = "name=" + userName, expdate = ";expires=Mon, 27 Mar 2017 13:00:00 UTC", newtext = encodeURIComponent(thetext); newtext += expdate; document.cookie = newtext; } //Reading & Writing cookie function read_it() { var rawCookie = document.cookie; bakedCookie = decodeURIComponent(rawCookie); yumCookie = bakedCookie.split("="); document.getElementById("greeting").innerHTML = "<p>Welcome, " + yumCookie[1] + "!</p>"; } if (document.cookie) { read_it(); } else { set_it(); read_it(); } 
 <!DOCTYPE html> <html> <head> <title>Page Title</title> </head> <body> <div id="greeting"> <script src="prjs13_2.js"></script> </div> </body> </html> 

尝试在控制台中仅运行此代码,然后看看您得到了什么-

 var userName = prompt("Please Enter Your Name", ""),
      thetext = "name=" + userName,
      expdate = ";expires=Mon, 27 Mar 2017 13:00:00 UTC",
      newtext = encodeURIComponent(thetext);
    newtext += expdate;
    document.cookie = newtext;

我用“大卫”这个名字来做的

name%3Ddavid; expires = Mon,27 Mar 2017 13:00:00 UTC“

设置Cookie时,您的名称属性无效。 尝试使用此代码(不使用encodeURIComponent和;而不是逗号)-

var userName = prompt("Please Enter Your Name", "");
var  thetext = "name=" + userName;
var expdate = ";expires=Mon, 27 Mar 2017 13:00:00 UTC";
var newtext = thetext;
document.cookie = newtext;

您可以使用以下功能获取/设置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;
}

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);
        }
    }
}

下面是一些小提琴例如: 小提琴

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