100個不能錯過的實用JS自定義函數

 本文收集了100個原生態JavaScript編寫的常用、實用自定義函數,需要的朋友可以參考下

1、原生JavaScript實現字符串長度截取   代碼如下: function cutstr(str, len) {     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獲取域名主機 代碼如下: 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  代碼如下: String.prototype.trim = function() {     var reExtraSpace = /^s*(.*?)s+$/;     return this.replace(reExtraSpace, "$1") } 4、原生JavaScript替換全部  代碼如下: String.prototype.replaceAll = function(s1, s2) {     return this.replace(new RegExp(s1, "gm"), s2) } 5、原生JavaScript轉義html標簽 代碼如下: function HtmlEncode(text) {     return text.replace(/&/g, '&').replace(/"/g, '"').replace(/</g, '<').replace(/>/g, '>') } 6、原生JavaScript還原html標簽  代碼如下: function HtmlDecode(text) {     return text.replace(/&/g, '&').replace(/"/g, '"').replace(/</g, '<').replace(/>/g, '>') } 7、原生JavaScript時間日期格式轉換 代碼如下: Date.prototype.Format = function(formatStr) {     var str = formatStr;     var Week = ['日', '一', '二', '三', '四', '五', '六'];     str = str.replace(/yyyy|YYYY/, this.getFullYear());     str = str.replace(/yy|YY/, (this.getYear() % 100) > 9 ? (this.getYear() % 100).toString() : '0' + (this.getYear() % 100));     str = str.replace(/MM/, (this.getMonth() + 1) > 9 ? (this.getMonth() + 1).toString() : '0' + (this.getMonth() + 1));     str = str.replace(/M/g, (this.getMonth() + 1));     str = str.replace(/w|W/g, Week[this.getDay()]);     str = str.replace(/dd|DD/, this.getDate() > 9 ? this.getDate().toString() : '0' + this.getDate());     str = str.replace(/d|D/g, this.getDate());     str = str.replace(/hh|HH/, this.getHours() > 9 ? this.getHours().toString() : '0' + this.getHours());     str = str.replace(/h|H/g, this.getHours());     str = str.replace(/mm/, this.getMinutes() > 9 ? this.getMinutes().toString() : '0' + this.getMinutes());     str = str.replace(/m/g, this.getMinutes());     str = str.replace(/ss|SS/, this.getSeconds() > 9 ? this.getSeconds().toString() : '0' + this.getSeconds());     str = str.replace(/s|S/g, this.getSeconds());     return str } 8、原生JavaScript判斷是否為數字類型  代碼如下: function isDigit(value) {     var patrn = /^[0-9]*$/;     if (patrn.exec(value) == null || value == "") {         return false     } else {         return true     } } 9、原生JavaScript設置cookie值  代碼如下: 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獲取cookie值  代碼如下: function getCookie(name) {     var arr = document.cookie.match(new RegExp("(^| )" + name + "=([^;]*)(;|$)"));     if (arr != null) return unescape(arr[2]);     return null } 11、原生JavaScript加入收藏夾  代碼如下: function AddFavorite(sURL, sTitle) {     try {         window.external.addFavorite(sURL, sTitle)     } catch(e) {         try {             window.sidebar.addPanel(sTitle, sURL, "")         } catch(e) {             alert("加入收藏失敗，請使用Ctrl+D進行添加")         }     } } 12、原生JavaScript設為首頁  代碼如下: function setHomepage() {     if (document.all) {         document.body.style.behavior = 'url(#default#homepage)';         document.body.setHomePage('http://www.jq-school.com')     } else if (window.sidebar) {         if (window.netscape) {             try {                 netscape.security.PrivilegeManager.enablePrivilege("UniversalXPConnect")             } catch(e) {                 alert("該操作被浏覽器拒絕，如果想啟用該功能，請在地址欄內輸入 about:config,然後將項 signed.applets.codebase_principal_support 值該為true")             }         }         var prefs = Components.classes['@mozilla.org/preferences-service;1'].getService(Components.interfaces.nsIPrefBranch);         prefs.setCharPref('browser.startup.homepage', 'http://www.jq-school.com')     } } 13、原生JavaScript判斷IE6 代碼如下: 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加載樣式文件 代碼如下: 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返回腳本內容  代碼如下: 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(