前端：分享一些实用的JS代码片段
今天给大家分享一些实用的JS代码片段，有需要的朋友欢迎收藏！
1、获取浏览器的版本
function getBrowser() {
var UserAgent = navigator.userAgent.toLowerCase();
var browserInfo = {};
var browserArray = {
IE: window.ActiveXObject || "ActiveXObject" in window, // IE
Chrome: UserAgent.indexOf('chrome') > -1 && UserAgent.indexOf('safari') > -1, // Chrome浏览器
Firefox: UserAgent.indexOf('firefox') > -1, // 火狐浏览器
Opera: UserAgent.indexOf('opera') > -1, // Opera浏览器
Safari: UserAgent.indexOf('safari') > -1 && UserAgent.indexOf('chrome') == -1, // safari浏览器
Edge: UserAgent.indexOf('edge') > -1, // Edge浏览器
QQBrowser: /qqbrowser/.test(UserAgent), // qq浏览器
WeixinBrowser: /MicroMessenger/i.test(UserAgent) // 微信浏览器
};
// console.log(browserArray)
for (var i in browserArray) {
if (browserArray[i]) {
var versions = '';
if (i == 'IE') {
versions = UserAgent.match(/(msie\s|trident.*rv:)([\w.]+)/)[2];
} else if (i == 'Chrome') {
for (var mt in navigator.mimeTypes) {
//检测是否是360浏览器(测试只有pc端的360才起作用)
if (navigator.mimeTypes[mt]['type'] == 'application/360softmgrplugin') {
i = '360';
}
}
versions = UserAgent.match(/chrome\/([\d.]+)/)[1];
} else if (i == 'Firefox') {
versions = UserAgent.match(/firefox\/([\d.]+)/)[1];
} else if (i == 'Opera') {
versions = UserAgent.match(/opera\/([\d.]+)/)[1];
} else if (i == 'Safari') {
versions = UserAgent.match(/version\/([\d.]+)/)[1];
} else if (i == 'Edge') {
versions = UserAgent.match(/edge\/([\d.]+)/)[1];
} else if (i == 'QQBrowser') {
versions = UserAgent.match(/qqbrowser\/([\d.]+)/)[1];
}
browserInfo.type = i;
browserInfo.versions = parseInt(versions);
}
}
return browserInfo;
}2、颜色RGB转十六进制
function colorRGBtoHex(color) {
var rgb = color.split(',');
var r = parseInt(rgb[0].split('(')[1]);
var g = parseInt(rgb[1]);
var b = parseInt(rgb[2].split(')')[0]);
var hex = "#" + ((1 << 24) + (r << 16) + (g << 8) + b).toString(16).slice(1);
return hex;
}3、禁止右键菜单代码、禁止复制粘贴代码
< script type = "text/javascript" >
//屏蔽右键菜单
document.oncontextmenu = function(event) {
if (window.event) {
event = window.event;
}
try {
var the = event.srcElement;
if (! ((the.tagName == "INPUT" && the.type.toLowerCase() == "text") || the.tagName == "TEXTAREA")) {
return false;
}
return true;
} catch(e) {
return false;
}
}
//屏蔽粘贴
document.onpaste = function(event) {
if (window.event) {
event = window.event;
}
try {
var the = event.srcElement;
if (! ((the.tagName == "INPUT" && the.type.toLowerCase() == "text") || the.tagName == "TEXTAREA")) {
return false;
}
return true;
} catch(e) {
return false;
}
}
//屏蔽复制
document.oncopy = function(event) {
if (window.event) {
event = window.event;
}
try {
var the = event.srcElement;
if (! ((the.tagName == "INPUT" && the.type.toLowerCase() == "text") || the.tagName == "TEXTAREA")) {
return false;
}
return true;
} catch(e) {
return false;
}
}
//屏蔽剪切
document.oncut = function(event) {
if (window.event) {
event = window.event;
}
try {
var the = event.srcElement;
if (! ((the.tagName == "INPUT" && the.type.toLowerCase() == "text") || the.tagName == "TEXTAREA")) {
return false;
}
return true;
} catch(e) {
return false;
}
}
//屏蔽选中
document.onselectstart = function(event) {
if (window.event) {
event = window.event;
}
try {
var the = event.srcElement;
if (! ((the.tagName == "INPUT" && the.type.toLowerCase() == "text") || the.tagName == "TEXTAREA")) {
return false;
}
return true;
} catch(e) {
return false;
}
} < /script>/
4、检查日期是否合法
function CheckDateTime(str){
var reg = /^(\d+)-(\d{1,2})-(\d{1,2}) (\d{1,2}):(\d{1,2}):(\d{1,2})$/;
var r = str.match(reg);
if(r==null)return false;
r[2]=r[2]-1;
var d= new Date(r[1], r[2],r[3], r[4],r[5], r[6]);
if(d.getFullYear()!=r[1])return false;
if(d.getMonth()!=r[2])return false;
if(d.getDate()!=r[3])return false;
if(d.getHours()!=r[4])return false;
if(d.getMinutes()!=r[5])return false;
if(d.getSeconds()!=r[6])return false;
return true;
}
5、英文字符串首字母大写
/**
* 方法一：js字符串切割
* @param {*} str
*/
function firstToUpper1(str) {
return str.trim().toLowerCase().replace(str[0], str[0].toUpperCase());
}
/**
* 方法二：js正则
* @param {*} str
*/
function firstToUpper2(str){
return str.replace(/\b(\w)(\w*)/g, function($0, $1, $2) {
return $1.toUpperCase() + $2.toLowerCase();
});
}
/**
* 方法三：js正则
* @param {*} str
*/
function firstToUpper3(str){
return str.toLowerCase().replace(/( |^)[a-z]/g,(L)=>L.toUpperCase());
}6、计算2个日期之间相差多少天
function getDays(strDateStart,strDateEnd){
var strSeparator = "-"; //日期分隔符
var oDate1;
var oDate2;
var iDays;
oDate1= strDateStart.split(strSeparator);
oDate2= strDateEnd.split(strSeparator);
var strDateS = new Date(oDate1[0], oDate1[1]-1, oDate1[2]);
var strDateE = new Date(oDate2[0], oDate2[1]-1, oDate2[2]);
iDays = parseInt(Math.abs(strDateS - strDateE ) / 1000 / 60 / 60 /24)//把相差的毫秒数转换为天数
return iDays ;
}7、生成随机十六进制颜色
function randomHexColor() {
//随机生成十六进制颜色
var hex = Math.floor(Math.random() * 16777216).toString(16);
//生成ffffff以内16进制数
while (hex.length < 6) {
//while循环判断hex位数，少于6位前面加0凑够6位 hex = '0' + hex; }
return '#' + hex; //返回‘#'开头16进制颜色
}8、数组去重
const removeDuplicates = (arr) => [...new Set(arr)];
console.log(removeDuplicates([1, 2, 3, 3, 4, 4, 5, 5, 6]));
// Result: [ 1, 2, 3, 4, 5, 6 ]9、从 URL 获取查询参数
function getParameterByName(name, url) {
if (!url) url = window.location.href;
name = name.replace(/[\[\]]/g, "\\$&");
var regex = new RegExp("[?&]" + name + "(=([^&#]*)|&|#|$)"),
results = regex.exec(url);
if (!results) return null;
if (!results[2]) return '';
return decodeURIComponent(results[2].replace(/\+/g, " "));
}10、校验数字是奇数还是偶数
const isEven = num => num % 2 === 0;
console.log(isEven(2));
// Result: True
11、求数字的平均值
const average = (...args) => args.reduce((a, b) => a + b) / args.length;
average(1, 2, 3, 4);
// Result: 2.512、回到顶部
function topFunction() {
document.body.scrollTop = 0;
document.documentElement.scrollTop = 0;
}
13、翻转字符串
// reverse
var name = "My city is WH";
var resultStr = name.split('').reverse().join('');
console.log(resultStr); // HW si ytic yM// charAt
var name = "My city is WuHan";
var nameArr = name.split('');
var resultStr = '';
for (var i = nameArr.length-1; i >= 0; i--) {
resultStr += name.charAt(i);
}
console.log(resultStr); // naHuW si ytic yM
14、校验数组是否为空
const isNotEmpty = arr => Array.isArray(arr) && arr.length > 0;
isNotEmpty([1, 2, 3]);
// Result: true
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原始发表：2021-10-31，如有侵权请联系 cloudcommunity@tencent.com 删除
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