Use JS to set cookies, read cookies, and delete cookies
JavaScript is a script that runs on the client side, so it is generally not possible to set up a Session because the Session runs on the server side.
And cookies run on the client, so you can use JS to set cookies.
Suppose there is such a situation, in a certain use case process, jump from page A to page B, if JS is used in page A The variable temp is used to save the value of a certain variable. When you are on page B, you also need to use JS to reference the variable value of temp. The life cycle of global variables or static variables in JS is limited. When a page jump occurs or When the page is closed, the values of these variables will be reloaded, that is, the saved effect will not be achieved. The best solution to this problem is to use cookies to save the value of the variable. So how to set and read cookies?
First of all, you need to understand the structure of cookies a little bit. Simply put: cookies are saved in the form of key-value pairs, that is, in the key=value format. Each cookie is usually separated by ";".
JS setting cookie:
Assume that in page A, you want to save the value of the variable username ("jack") to the cookie, and the key value is name, then the corresponding JS code is:
document.cookie="name="+ username;
JS reads cookie:
Assume that the content stored in the cookie is: name=jack; password=123
Then the JS code to get the value of the variable username in page B is as follows:
var username=document.cookie.split(";")[0].split("=")[1]; //JS操作cookies方法! //写cookies function setCookie(name,value) { var Days = 30; var exp = new Date(); exp.setTime(exp.getTime() + Days*24*60*60*1000); document.cookie = name + "="+ escape (value) + ";expires=" + exp.toGMTString(); } //读取cookies function getCookie(name) { var arr,reg=new RegExp("(^| )"+name+"=([^;]*)(;|$)"); if(arr=document.cookie.match(reg)) return unescape(arr[2]); else return null; } //删除cookies function delCookie(name) { var exp = new Date(); exp.setTime(exp.getTime() - 1); var cval=getCookie(name); if(cval!=null) document.cookie= name + "="+cval+";expires="+exp.toGMTString(); } //使用示例 setCookie("name","hayden"); alert(getCookie("name")); //如果需要设定自定义过期时间 //那么把上面的setCookie 函数换成下面两个函数就ok; //程序代码 function setCookie(name,value,time) { var strsec = getsec(time); var exp = new Date(); exp.setTime(exp.getTime() + strsec*1); document.cookie = name + "="+ escape (value) + ";expires=" + exp.toGMTString(); } function getsec(str) { alert(str); var str1=str.substring(1,str.length)*1; var str2=str.substring(0,1); if (str2=="s") { return str1*1000; } else if (str2=="h") { return str1*60*60*1000; } else if (str2=="d") { return str1*24*60*60*1000; } }
//这是有设定过期时间的使用示例: //s20是代表20秒 //h是指小时,如12小时则是:h12 //d是天数,30天则:d30 setCookie(“name”,”hayden”,”s20”);

去掉重复并排序的方法:1、使用“Array.from(new Set(arr))”或者“[…new Set(arr)]”语句,去掉数组中的重复元素,返回去重后的新数组;2、利用sort()对去重数组进行排序,语法“去重数组.sort()”。

本篇文章给大家带来了关于JavaScript的相关知识,其中主要介绍了关于Symbol类型、隐藏属性及全局注册表的相关问题,包括了Symbol类型的描述、Symbol不会隐式转字符串等问题,下面一起来看一下,希望对大家有帮助。

怎么制作文字轮播与图片轮播?大家第一想到的是不是利用js,其实利用纯CSS也能实现文字轮播与图片轮播,下面来看看实现方法,希望对大家有所帮助!

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方法:1、利用“点击元素对象.unbind("click");”方法,该方法可以移除被选元素的事件处理程序;2、利用“点击元素对象.off("click");”方法,该方法可以移除通过on()方法添加的事件处理程序。

本篇文章给大家带来了关于JavaScript的相关知识,其中主要介绍了关于BOM操作的相关问题,包括了window对象的常见事件、JavaScript执行机制等等相关内容,下面一起来看一下,希望对大家有帮助。

foreach不是es6的方法。foreach是es3中一个遍历数组的方法,可以调用数组的每个元素,并将元素传给回调函数进行处理,语法“array.forEach(function(当前元素,索引,数组){...})”;该方法不处理空数组。


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