JavaScript实用功能代码片段整理二

31、原生JavaScript判断是否移动设备

 functionisMobile(){
     if(typeof this._isMobile === 'boolean'){
        return this._isMobile;
     }
     varscreenWidth = this.getScreenWidth();
     varfixViewPortsExperiment = rendererModel.runningExperiments.FixViewport ||rendererModel.runningExperiments.fixviewport;
     varfixViewPortsExperimentRunning = fixViewPortsExperiment &&(fixViewPortsExperiment.toLowerCase() === "new");
    if(!fixViewPortsExperiment){
        if(!this.isAppleMobileDevice()){
            screenWidth = screenWidth/window.devicePixelRatio;
         }
     }
     varisMobileScreenSize = screenWidth < 600;
     varisMobileUserAgent = false;
    this._isMobile = isMobileScreenSize && this.isTouchScreen();
     returnthis._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 && documentinstanceof DocumentTouch);
}

36、原生JavaScript判断是否在安卓上的谷歌浏览器

 functionisNewChromeOnAndroid(){
    if(this.isAndroidMobileDevice()){
         varuserAgent = 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;
             }
         }
     }
     returnfalse;
 }

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

 functiongetInitZoom(){
    if(!this._initZoom){
         varscreenWidth = Math.min(screen.height, screen.width);
        if(this.isAndroidMobileDevice() &&!this.isNewChromeOnAndroid()){
            screenWidth = screenWidth/window.devicePixelRatio;
         }
        this._initZoom = screenWidth /document.body.offsetWidth;
     }
     returnthis._initZoom;
 }

39、原生JavaScript获取移动设备最大化大小

 functiongetZoom(){
     varscreenWidth = (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;
     }
     varFixViewPortsExperiment = rendererModel.runningExperiments.FixViewport ||rendererModel.runningExperiments.fixviewport;
     varFixViewPortsExperimentRunning = 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

 functiongetScreenWidth(){
     varsmallerSide = Math.min(screen.width, screen.height);
     varfixViewPortsExperiment = rendererModel.runningExperiments.FixViewport ||rendererModel.runningExperiments.fixviewport;
     varfixViewPortsExperimentRunning = fixViewPortsExperiment &&(fixViewPortsExperiment.toLowerCase() === "new");
    if(fixViewPortsExperiment){
        if(this.isAndroidMobileDevice() &&!this.isNewChromeOnAndroid()){
            smallerSide = smallerSide/window.devicePixelRatio;
         }
     }
     returnsmallerSide;
 }

41、原生JavaScript完美判断是否为网址

function IsURL(strUrl) {
    varregular =/^\b(((https?|ftp):\/\/)?[-a-z0-9]+(\.[-a-z0-9]+)*\.(?:com|edu|gov|int|mil|net|org|biz|info|name|museum|asia|coop|aero|[a-z][a-z]|((25[0-5])|(2[0-4]\d)|(1\d\d)|([1-9]\d)|\d))\b(\/[-a-z0-9_:\@&?=+,.!\/~%\$]*)?)$/i
    if(regular.test(strUrl)) {
        returntrue;
    }
    else {
        returnfalse;
    }
}

42、原生JavaScript根据样式名称检索元素对象

 functiongetElementsByClassName(name) {
     var tags= document.getElementsByTagName('*') || document.all;
     var els =[];
     for (vari = 0; i < tags.length; i++) {
         if(tags[i].className) {
            var cs = tags[i].className.split(' ');
            for (var j = 0; j < cs.length; j++) {
                if (name == cs[j]) {
                    els.push(tags[i]);
                    break
                }
             }
         }
     }
     returnels
 }

43、原生JavaScript判断是否以某个字符串开头

String.prototype.startWith = function (s) {
    returnthis.indexOf(s) == 0
}

44、原生JavaScript判断是否以某个字符串结束

String.prototype.endWith = function (s) {
    var d =this.length - s.length;
    return (d>= 0 && this.lastIndexOf(s) == d)
}

45、原生JavaScript返回IE浏览器的版本号

function getIE(){
    if(window.ActiveXObject){
        var v= navigator.userAgent.match(/MSIE ([^;]+)/)[1];
        returnparseFloat(v.substring(0, v.indexOf(".")))
    }
    returnfalse
}

46、原生JavaScript获取页面高度

function getPageHeight(){
    var g =document, a = g.body, f = g.documentElement, d = g.compatMode =="BackCompat"
            ?a
            :g.documentElement;
    returnMath.max(f.scrollHeight, a.scrollHeight, d.clientHeight);
}

47、原生JavaScript获取页面scrollLeft

function getPageScrollLeft(){
    var a =document;
    returna.documentElement.scrollLeft || a.body.scrollLeft;
}

48、原生JavaScript获取页面可视宽度

function getPageViewWidth(){
    var d =document, a = d.compatMode == "BackCompat"
            ?d.body
            :d.documentElement;
    returna.clientWidth;
}

49、原生JavaScript获取页面宽度

function getPageWidth(){
    var g =document, a = g.body, f = g.documentElement, d = g.compatMode =="BackCompat"
            ?a
            :g.documentElement;
    returnMath.max(f.scrollWidth, a.scrollWidth, d.clientWidth);
}

50、原生JavaScript获取页面scrollTop

function getPageScrollTop(){
    var a =document;
    returna.documentElement.scrollTop || a.body.scrollTop;
}

51、原生JavaScript获取页面可视高度

function getPageViewHeight() {
    var d =document, a = d.compatMode == "BackCompat"
            ?d.body
            :d.documentElement;
    returna.clientHeight;
}

52、原生JavaScript跨浏览器添加事件

 functionaddEvt(oTarget,sEvtType,fnHandle){
    if(!oTarget){return;}
    if(oTarget.addEventListener){
        oTarget.addEventListener(sEvtType,fnHandle,false);
     }elseif(oTarget.attachEvent){
        oTarget.attachEvent("on" + sEvtType,fnHandle);
     }else{
        oTarget["on" + sEvtType] = fnHandle;
     }
 }

53、原生JavaScript跨浏览器删除事件

 functiondelEvt(oTarget,sEvtType,fnHandle){
    if(!oTarget){return;}
    if(oTarget.addEventListener){
        oTarget.addEventListener(sEvtType,fnHandle,false);
     }elseif(oTarget.attachEvent){
        oTarget.attachEvent("on" + sEvtType,fnHandle);
     }else{
        oTarget["on" + sEvtType] = fnHandle;
     }
 }

54、原生JavaScript去掉url前缀

function removeUrlPrefix(a){
 a=a.replace(/：/g,":").replace(/．/g,".").replace(/／/g,"/");
 while(trim(a).toLowerCase().indexOf("http://")==0){
   a=trim(a.replace(/http:\/\//i,""));
  }
  return a;
}

55、原生JavaScript随机数时间戳

function uniqueId(){
    vara=Math.random,b=parseInt;
    returnNumber(new Date()).toString()+b(10*a())+b(10*a())+b(10*a());
}

56、原生JavaScript全角半角转换,iCase:0全到半，1半到全，其他不转化

 functionchgCase(sStr,iCase){
     if(typeofsStr != "string" || sStr.length <= 0 || !(iCase === 0 || iCase ==1)){
        return sStr;
     }
     vari,oRs=[],iCode;
    if(iCase){/*半->全*/
        for(i=0; i<sStr.length;i+=1){ 
            iCode = sStr.charCodeAt(i);
            if(iCode == 32){
                iCode = 12288;              
            }else if(iCode < 127){
                iCode += 65248;
             }
            oRs.push(String.fromCharCode(iCode)); 
        }       
    }else{/*全->半*/
        for(i=0; i<sStr.length;i+=1){ 
            iCode = sStr.charCodeAt(i);
            if(iCode == 12288){
                iCode = 32;
            }else if(iCode > 65280 && iCode < 65375){
                iCode -= 65248;             
             }
            oRs.push(String.fromCharCode(iCode)); 
        }       
     }       
     returnoRs.join("");        
 }

57、原生JavaScript确认是否键盘有效输入值

 functioncheckKey(iKey){
     if(iKey== 32 || iKey == 229){return true;}/*空格和异常*/
    if(iKey>47 && iKey < 58){return true;}/*数字*/
    if(iKey>64 && iKey < 91){return true;}/*字母*/
    if(iKey>95 && iKey < 108){return true;}/*数字键盘1*/
    if(iKey>108 && iKey < 112){return true;}/*数字键盘2*/
    if(iKey>185 && iKey < 193){return true;}/*符号1*/
    if(iKey>218 && iKey < 223){return true;}/*符号2*/
     returnfalse;
 }

58、原生JavaScript获取网页被卷去的位置

function getScrollXY() {
    returndocument.body.scrollTop ? {
        x:document.body.scrollLeft,
        y:document.body.scrollTop
    }: {
        x:document.documentElement.scrollLeft,
        y:document.documentElement.scrollTop
    }
}

59、原生JavaScript另一种正则日期格式化函数+调用方法

 Date.prototype.format = function(format){//author: meizz
   var o = {
    "M+" : this.getMonth()+1, //month
    "d+" : this.getDate(),   //day
    "h+" : this.getHours(),  //hour
    "m+" : this.getMinutes(), //minute
    "s+" : this.getSeconds(), //second
    "q+" : Math.floor((this.getMonth()+3)/3),  //quarter
    "S" : this.getMilliseconds() //millisecond
   }
  if(/(y+)/.test(format)) format=format.replace(RegExp.$1,
    (this.getFullYear()+"").substr(4 - RegExp.$1.length));
   for(var kin o)if(new RegExp("("+ k +")").test(format))
     format =format.replace(RegExp.$1,
      RegExp.$1.length==1 ? o[k] :
        ("00"+ o[k]).substr((""+ o[k]).length));
   returnformat;
 }
 alert(newDate().format("yyyy-MM-dd hh:mm:ss"));

60、原生JavaScript时间个性化输出功能

 /*
 1、< 60s,显示为“刚刚”
 2、>= 1min&& < 60 min, 显示与当前时间差“XX分钟前”
 3、>= 60min&& < 1day, 显示与当前时间差“今天 XX:XX”
 4、>= 1day&& < 1year, 显示日期“XX月XX日 XX:XX”
 5、>=1year, 显示具体日期“XXXX年XX月XX日 XX:XX”
  */
 functiontimeFormat(time){
   var date =new Date(time)
     , curDate= new Date()
     , year =date.getFullYear()
     , month =date.getMonth() + 1
     , day =date.getDate()
     , hour =date.getHours()
     , minute= date.getMinutes()
     , curYear= curDate.getFullYear()
     , curHour= curDate.getHours()
     ,timeStr;
  
   if(year< curYear){
     timeStr =year +'年'+ month +'月'+ day +'日 '+ hour +':'+ minute;
   }else{
     varpastTime = curDate - date
       , pastH= pastTime/3600000;
  
     if(pastH> curHour){
       timeStr= month +'月'+ day +'日 '+ hour +':'+ minute;
     }elseif(pastH >= 1){
       timeStr= '今天 ' + hour +':'+ minute +'分';
     }else{
       varpastM = curDate.getMinutes() - minute;
      if(pastM > 1){
        timeStr = pastM +'分钟前';
       }else{
        timeStr = '刚刚';
       }
     }
   }
   returntimeStr;
 } 

原文来自：

http://www.jq-school.com/Show.aspx?id=316