32、可以拿来用的JavaScript实用功能代码

可以拿来用的JavaScript实用功能代码(可能会有些bug，用时稍微修改下，我用了几个还可以）

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1、原生JavaScript实现字符串长度截取

function cutstr(str, len) { //str：截取的字符串 len：截取的长度为len-1
    var temp;
    var icount = 0;
    var patrn = /[^\x00-\xff]/;
    var strre = "";
    for (var i = 0; i < str.length; i++) {
        if (icount < len - 1) {
            temp = str.substr(i, 1);
            if (patrn.exec(temp) == null) {
                icount = icount + 1
            } else {
                icount = icount + 2
            }
            strre += temp
        } else {
            break
        }
    }
    return strre + "..."
}

2、原生JavaScript获取域名主机

function getHost(url) {
    var host = "null";
    if(typeof url == "undefined"|| null == url) {
        url = window.location.href;
    }
    var regex = /^\w+\:\/\/([^\/]*).*/;
    var match = url.match(regex);
    if(typeof match != "undefined" && null != match) {
        host = match[1];
    }
    return host;
}

3、原生JavaScript清除空格

String.prototype.trim = function() {
    var reExtraSpace = /^\s*(.*?)\s+$/;
    return this.replace(reExtraSpace, "$1")
}

4、原生JavaScript替换全部

String.prototype.replaceAll = function(s1, s2) {
    return this.replace(new RegExp(s1, "gm"), s2)
}

5、原生JavaScript转义html标签

function HtmlEncode(text) { // 字符串html转成html可读的text
    return text.replace(/&/g, '&amp').replace(/\"/g, '&quot;').replace(/</g, '&lt;').replace(/>/g, '&gt;')
}

6、原生JavaScript还原html标签

function HtmlDecode(text) { // '&lt;div&gt;1&lt;/div&gt;'  => "<div>1</div>"
    return text.replace(/&amp;/g, '&').replace(/&quot;/g, '\"').replace(/&lt;/g, '<').replace(/&gt;/g, '>')
}

7、原生JavaScript时间日期格式转换

Date.prototype.Format = function(formatStr) {
    var str = formatStr;
    var Week = ['日', '一', '二', '三', '四', '五', '六'];
    str = str.replace(/yyyy|YYYY/, this.getFullYear());
    str = str.replace(/yy|YY/, (this.getYear() % 100) > 9 ? (this.getYear() % 100).toString() : '0' + (this.getYear() % 100));
    str = str.replace(/MM/, (this.getMonth() + 1) > 9 ? (this.getMonth() + 1).toString() : '0' + (this.getMonth() + 1));
    str = str.replace(/M/g, (this.getMonth() + 1));
    str = str.replace(/w|W/g, Week[this.getDay()]);
    str = str.replace(/dd|DD/, this.getDate() > 9 ? this.getDate().toString() : '0' + this.getDate());
    str = str.replace(/d|D/g, this.getDate());
    str = str.replace(/hh|HH/, this.getHours() > 9 ? this.getHours().toString() : '0' + this.getHours());
    str = str.replace(/h|H/g, this.getHours());
    str = str.replace(/mm/, this.getMinutes() > 9 ? this.getMinutes().toString() : '0' + this.getMinutes());
    str = str.replace(/m/g, this.getMinutes());
    str = str.replace(/ss|SS/, this.getSeconds() > 9 ? this.getSeconds().toString() : '0' + this.getSeconds());
    str = str.replace(/s|S/g, this.getSeconds());
    return str
}

8、原生JavaScript判断是否为数字类型

function isDigit(value) {
    var patrn = /^[0-9]*$/;
    if (patrn.exec(value) === null || value === "") {
        return false
    } else {
        return true
    }
}

9、原生JavaScript设置cookie值

function setCookie(name, value, Hours) {
    var d = new Date();
    var offset = 8;
    var utc = d.getTime() + (d.getTimezoneOffset() * 60000);
    var nd = utc + (3600000 * offset);
    var exp = new Date(nd);
    exp.setTime(exp.getTime() + Hours * 60 * 60 * 1000);
    document.cookie = name + "=" + escape(value) + ";path=/;expires=" + exp.toGMTString() + ";domain=360doc.com;"
}

10、原生JavaScript获取cookie值

function getCookie(name) {
    var arr = document.cookie.match(new RegExp("(^| )" + name + "=([^;]*)(;|$)"));
    if (arr != null) return unescape(arr[2]);
    return null
}

11、原生JavaScript加入收藏夹

function AddFavorite(sURL, sTitle) {
    try {
        window.external.addFavorite(sURL, sTitle)
    } catch(e) {
        try {
            window.sidebar.addPanel(sTitle, sURL, "")
        } catch(e) {
            alert("加入收藏失败，请使用Ctrl+D进行添加")
        }
    }
}

12、原生JavaScript设为首页

function setHomepage() {
    if (document.all) {
        document.body.style.behavior = 'url(#default#homepage)';
        document.body.setHomePage('http://www.baidu.com')
    } else if (window.sidebar) {
        if (window.netscape) {
            try {
                netscape.security.PrivilegeManager.enablePrivilege("UniversalXPConnect")
            } catch(e) {
                alert("该操作被浏览器拒绝，如果想启用该功能，请在地址栏内输入 about:config,然后将项 signed.applets.codebase_principal_support 值该为true")
            }
        }
        var prefs = Components.classes['@mozilla.org/preferences-service;1'].getService(Components.interfaces.nsIPrefBranch);
        prefs.setCharPref('browser.startup.homepage', 'http://www.baidu.com')
    }
}

13、原生JavaScript判断IE6

var ua = navigator.userAgent.toLowerCase();
var isIE6 = ua.indexOf("msie 6") > -1;
if (isIE6) {
    try {
        document.execCommand("BackgroundImageCache", false, true)
    } catch(e) {}
}

14、原生JavaScript加载样式文件

function LoadStyle(url) {
    try {
        document.createStyleSheet(url)
    } catch(e) {
        var cssLink = document.createElement('link');
        cssLink.rel = 'stylesheet';
        cssLink.type = 'text/css';
        cssLink.href = url;
        var head = document.getElementsByTagName('head')[0];
        head.appendChild(cssLink)
    }
}

15、原生JavaScript返回脚本内容

function evalscript(s) {
	if(s.indexOf('<script') == -1) return s;
	var p = /<script[^\>]*?>([^\x00]*?)<\/script>/ig;
	var arr = [];
	while(arr = p.exec(s)) {
		var p1 = /<script[^\>]*?src=\"([^\>]*?)\"[^\>]*?(reload=\"1\")?(?:charset=\"([\w\-]+?)\")?><\/script>/i;
		var arr1 = [];
		arr1 = p1.exec(arr[0]);
		if(arr1) {
			appendscript(arr1[1], '', arr1[2], arr1[3]);
		} else {
			p1 = /<script(.*?)>([^\x00]+?)<\/script>/i;
			arr1 = p1.exec(arr[0]);
			appendscript('', arr1[2], arr1[1].indexOf('reload=') != -1);
		}
	}
	return s;
}

16、原生JavaScript清除脚本内容

function stripscript(s) {
	return s.replace(/<script.*?>.*?<\/script>/ig, '');
}

17、原生JavaScript动态加载脚本文件

function appendscript(src, text, reload, charset) {
	var id = hash(src + text);
	if(!reload && in_array(id, evalscripts)) return;
	if(reload && $(id)) {
		$(id).parentNode.removeChild($(id));
	}

	evalscripts.push(id);
	var scriptNode = document.createElement("script");
	scriptNode.type = "text/javascript";
	scriptNode.id = id;
	scriptNode.charset = charset ? charset : (BROWSER.firefox ? document.characterSet : document.charset);
	try {
		if(src) {
			scriptNode.src = src;
			scriptNode.onloadDone = false;
			scriptNode.onload = function () {
				scriptNode.onloadDone = true;
				JSLOADED[src] = 1;
			};
			scriptNode.onreadystatechange = function () {
				if((scriptNode.readyState == 'loaded' || scriptNode.readyState == 'complete') && !scriptNode.onloadDone) {
					scriptNode.onloadDone = true;
					JSLOADED[src] = 1;
				}
			};
		} else if(text){
			scriptNode.text = text;
		}
		document.getElementsByTagName('head')[0].appendChild(scriptNode);
	} catch(e) {}
}

18、原生JavaScript返回按ID检索的元素对象

function $(id) {
	return !id ? null : document.getElementById(id);
}

19、原生JavaScript返回浏览器版本内容

function browserVersion(types) {
	var other = 1;
	for(i in types) {
		var v = types[i] ? types[i] : i;
		if(USERAGENT.indexOf(v) != -1) {
			var re = new RegExp(v + '(\\/|\\s)([\\d\\.]+)', 'ig');
			var matches = re.exec(USERAGENT);
			var ver = matches != null ? matches[2] : 0;
			other = ver !== 0 && v != 'mozilla' ? 0 : other;
		}else {
			var ver = 0;
		}
		eval('BROWSER.' + i + '= ver');
	}
	BROWSER.other = other;
}

20、原生JavaScript元素显示的通用方法

function $(id) {
	return !id ? null : document.getElementById(id);
}
function display(id) {
	var obj = $(id);
	if(obj.style.visibility) {
		obj.style.visibility = obj.style.visibility == 'visible' ? 'hidden' : 'visible';
	} else {
		obj.style.display = obj.style.display == '' ? 'none' : '';
	}
}

21、原生JavaScript中有insertBefore方法,可惜却没有insertAfter方法?用如下函数实现

function insertAfter(newChild,refChild){
	var parElem=refChild.parentNode;
	if(parElem.lastChild==refChild){
		refChild.appendChild(newChild);
	}else{
		parElem.insertBefore(newChild,refChild.nextSibling);
	}
}

22、原生JavaScript中兼容浏览器绑定元素事件

function addEventSamp(obj,evt,fn){
	if (obj.addEventListener) {
		obj.addEventListener(evt, fn, false);
	}else if(obj.attachEvent){
		obj.attachEvent('on'+evt,fn);
	}
}

23、原生JavaScript光标停在文字的后面，文本框获得焦点时调用

function focusLast(){
	var e = event.srcElement;
	var r =e.createTextRange();
	r.moveStart('character',e.value.length);
	r.collapse(true);
	r.select();
}

24、原生JavaScript检验URL链接是否有效

function getUrlState(URL){
	var xmlhttp = new ActiveXObject("microsoft.xmlhttp");
	xmlhttp.Open("GET",URL, false);
	try{
		xmlhttp.Send();
	}catch(e){
	}finally{
		var result = xmlhttp.responseText;
		if(result){
			if(xmlhttp.Status==200){
				return(true);
			}else{
				return(false);
			}
		}else{
			return(false);
		}
	}
}

25、原生JavaScript格式化CSS样式代码

function formatCss(s){//格式化代码
	s = s.replace(/\s*([\{\}\:\;\,])\s*/g, "$1");
	s = s.replace(/;\s*;/g, ";"); //清除连续分号
	s = s.replace(/\,[\s\.\#\d]*{/g, "{");
	s = s.replace(/([^\s])\{([^\s])/g, "$1 {\n\t$2");
	s = s.replace(/([^\s])\}([^\n]*)/g, "$1\n}\n$2");
	s = s.replace(/([^\s]);([^\s\}])/g, "$1;\n\t$2");
	return s;
}

26、原生JavaScript压缩CSS样式代码

function yasuoCss (s) {//压缩代码
	s = s.replace(/\/\*(.|\n)*?\*\//g, ""); //删除注释
	s = s.replace(/\s*([\{\}\:\;\,])\s*/g, "$1");
	s = s.replace(/\,[\s\.\#\d]*\{/g, "{"); //容错处理
	s = s.replace(/;\s*;/g, ";"); //清除连续分号
	s = s.match(/^\s*(\S+(\s+\S+)*)\s*$/); //去掉首尾空白
	return (s == null) ? "" : s[1];
}

27、原生JavaScript获取当前路径

var currentPageUrl = "";
if (typeof this.href === "undefined") {
    currentPageUrl = document.location.toString().toLowerCase();
}
else {
    currentPageUrl = this.href.toString().toLowerCase();
}

28、原生JavaScriptIP转成整型

function _ip2int(ip){
    var num = 0;
    ip = ip.split(".");
    num = Number(ip[0]) * 256 * 256 * 256 + Number(ip[1]) * 256 * 256 + Number(ip[2]) * 256 + Number(ip[3]);
    num = num >>> 0;
    return num;
}

29、原生JavaScript整型解析为IP地址

function _int2iP(num){
    var str;
    var tt = new Array();
    tt[0] = (num >>> 24) >>> 0;
    tt[1] = ((num << 8) >>> 24) >>> 0;
    tt[2] = (num << 16) >>> 24;
    tt[3] = (num << 24) >>> 24;
    str = String(tt[0]) + "." + String(tt[1]) + "." + String(tt[2]) + "." + String(tt[3]);
    return str;
}

30、原生JavaScript实现checkbox全选与全不选

function checkAll() {
	var selectall = document.getElementById("selectall");
	var allbox = document.getElementsByName("allbox");
	if (selectall.checked) {
		for (var i = 0; i < allbox.length; i++) {
			allbox[i].checked = true;
		}
	} else {
		for (var i = 0; i < allbox.length; i++) {
			allbox[i].checked = false;
		}
	}
}

移动篇

31、原生JavaScript判断是否移动设备

function isMobile(){
	if (typeof this._isMobile === 'boolean'){
		return this._isMobile;
	}
	var screenWidth = this.getScreenWidth();
	var fixViewPortsExperiment = rendererModel.runningExperiments.FixViewport || rendererModel.runningExperiments.fixviewport;
	var fixViewPortsExperimentRunning = fixViewPortsExperiment && (fixViewPortsExperiment.toLowerCase() === "new");
	if(!fixViewPortsExperiment){
		if(!this.isAppleMobileDevice()){
			screenWidth = screenWidth/window.devicePixelRatio;
		}
	}
	var isMobileScreenSize = screenWidth < 600;
	var isMobileUserAgent = false;
	this._isMobile = isMobileScreenSize && this.isTouchScreen();
	return this._isMobile;
}

32、原生JavaScript判断是否移动设备访问

function isMobileUserAgent(){
	return (/iphone|ipod|android.*mobile|windows.*phone|blackberry.*mobile/i.test(window.navigator.userAgent.toLowerCase()));
}

33、原生JavaScript判断是否苹果移动设备访问

function isAppleMobileDevice(){
	return (/iphone|ipod|ipad|Macintosh/i.test(navigator.userAgent.toLowerCase()));
}

34、原生JavaScript判断是否安卓移动设备访问

function isAndroidMobileDevice(){
	return (/android/i.test(navigator.userAgent.toLowerCase()));
}

35、原生JavaScript判断是否Touch屏幕

function isTouchScreen(){
	return (('ontouchstart' in window) || window.DocumentTouch && document instanceof DocumentTouch);
}

36、原生JavaScript判断是否在安卓上的谷歌浏览器

function isNewChromeOnAndroid(){
	if(this.isAndroidMobileDevice()){
		var userAgent = navigator.userAgent.toLowerCase();
		if((/chrome/i.test(userAgent))){
			var parts = userAgent.split('chrome/');

			var fullVersionString = parts[1].split(" ")[0];
			var versionString = fullVersionString.split('.')[0];
			var version = parseInt(versionString);

			if(version >= 27){
				return true;
			}
		}
	}
	return false;
}

37、原生JavaScript判断是否打开视窗

function isViewportOpen() {
	return !!document.getElementById('wixMobileViewport');
}

38、原生JavaScript获取移动设备初始化大小

function getInitZoom(){
	if(!this._initZoom){
		var screenWidth = Math.min(screen.height, screen.width);
		if(this.isAndroidMobileDevice() && !this.isNewChromeOnAndroid()){
			screenWidth = screenWidth/window.devicePixelRatio;
		}
		this._initZoom = screenWidth /document.body.offsetWidth;
	}
	return this._initZoom;
}

39、原生JavaScript获取移动设备最大化大小

function getZoom(){
	var screenWidth = (Math.abs(window.orientation) === 90) ? Math.max(screen.height, screen.width) : Math.min(screen.height, screen.width);
	if(this.isAndroidMobileDevice() && !this.isNewChromeOnAndroid()){
		screenWidth = screenWidth/window.devicePixelRatio;
	}
	var FixViewPortsExperiment = rendererModel.runningExperiments.FixViewport || rendererModel.runningExperiments.fixviewport;
	var FixViewPortsExperimentRunning = FixViewPortsExperiment && (FixViewPortsExperiment === "New" || FixViewPortsExperiment === "new");
	if(FixViewPortsExperimentRunning){
		return screenWidth / window.innerWidth;
	}else{
		return screenWidth / document.body.offsetWidth;
	}
}

40、原生JavaScript获取移动设备屏幕宽度

function getScreenWidth(){
	var smallerSide = Math.min(screen.width, screen.height);
	var fixViewPortsExperiment = rendererModel.runningExperiments.FixViewport || rendererModel.runningExperiments.fixviewport;
	var fixViewPortsExperimentRunning = fixViewPortsExperiment && (fixViewPortsExperiment.toLowerCase() === "new");
	if(fixViewPortsExperiment){
		if(this.isAndroidMobileDevice() && !this.isNewChromeOnAndroid()){
			smallerSide = smallerSide/window.devicePixelRatio;
		}
	}
	return smallerSide;
}

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