JS常用代码

摘要：返回指定范围的随机数之间的公式会阻挡预设要发生的事件会阻挡发生冒泡事件而则是前面两者的事情他都会做他会做他会做停止的执行并且立即回来防止被嵌套两种图片加载的方式第一个中级交流群成都猎巫第二个上海准备为图片预加载使用的插件使用的图片

返回指定范围的随机数(m-n之间)的公式

Math.random()*(n-m)+m

return false

return false

// event.preventDefault()会阻挡预设要发生的事件.
// event.stopPropagation()会阻挡发生冒泡事件.
// 而return false则是前面两者的事情他都会做：
// 他会做event.preventDefault();
// 他会做event.stopPropagation();
// 停止callback function的执行并且立即return回来

防止被Iframe嵌套

if(top != self){
    location.href = ”about:blank”;
}

两种图片lazy加载的方式
第一个By JS中级交流群 成都-猎巫 第二个By 上海-zenki

// @description 准备为图片预加载使用的插件
// 使用的图片容器css类名为lazy-load-wrap
// 图片真实地址为data-lazy-src
// 当lazy-load-wrap容器进入视口，则开始替换容器内所有需要延迟加载的图片路径，并更改容器的加载状态
//第一种方法
$.fn.compassLazyLoad=function(){
    var _HEIGHT=window.innerHeight,
    _lazyLoadWrap=$(".lazy-load-wrap");

    var methods={
        setOffsetTop:function(){
            $.each(_lazyLoadWrap,function(i,n){
                $(n).attr({
                    "top":n.offsetTop-_HEIGHT,
                    "status":"wait"
                });
            })
        },
        isShow:function(){
            var _scrollTop=$(window).scrollTop;
            //利用image容器判断是否进入视口，而非image本身
            $.each(_lazyLoadWrap,function(){
                var _that=$(this);
                if (_that.attr("status")==="done") {
                    return;
                };
                if (_that.attr("top")<=_scrollTop) {
                    _that.find("img[data-lazy-src]").each(function(i,n){
                        n.src=$(n).data("lazy-src");
                    });
                    _that.attr("status","done");
                };
            })
        },
        scroll:function(){
            $(window).on("scroll",function(){
                methods.isShow();
            });
        },
        init:function(){
            methods.setOffsetTop();
            methods.isShow();
            methods.scroll();
        }
    };
    methods.init();

}


//第二种方法

var exist=(function($){
    var timer=null,
    temp=[].slice.call($(".container"));
    ret={};

    for(var i=0,len=temp.length-1;i<=len;i++){
        ret[i]=temp[i];
    }
    var isExist=function(winTop,winEnd){
        for(var i in ret){
            console.log(ret);
            var item=ret[i],
            eleTop=item.offsetTop,
            eleEnd=eleTop+item.offsetHeight;

            if((eleTop>winTop&&eleTop<=winEnd)||(eleEnd>winTop&&eleEnd<=winEnd)){
                $(item).css("background","none");
                new Tab($(item).attr("id"),data).init;
                delete ret[i];
            }
        }
    }
    return {
        timer:timer;
        isExist:isExist;
    };
})($);



//第三种方法
Zepto(function ($) {
    var swiper = new Swiper(".swiper-container", {
        pagination: ".swiper-pagination",
        paginationClickable: true,
        autoplay: 3000,
        loop: true,
        autoplayDisableOnInteraction: false
    });
    (function lazyLoad() {
        var imgs = $(".lazyLoad");
        var src = "";
        $.each(imgs, function (index, item) {
            src = $(item).attr("data-src");
            $(item).attr("src", src);
        });
    })();
});
$(function () {
    var lazyLoadTimerId = null;
    /// 智能加载事件
    $(window).bind("scroll", function () {
        clearTimeout(lazyLoadTimerId);
        lazyLoadTimerId = setTimeout(function () {
            // 延迟加载所有图片
            var isHttp = (location.protocol === "http:");
            $("#ym_images img").each(function () {
                var self = $(this);
                if (self.filter(":above-the-fold").length > 0) {
                    var originUrl = self.attr("data-original");
                    self.attr("src", originUrl);
                }
            });
        }, 500);
    });
});

某年某月的1号为星期几

var weekday = ["星期日", "星期一", "星期二", "星期三", "星期四", "星期五", "星期六"];
weekday[new Date(2015, 9, 1).getDay()];    //2015年10月1号

js 判断IOS, 安卓

var u = navigator.userAgent, app = navigator.appVersion;
var isAndroid = u.indexOf("Android") > -1 || u.indexOf("Linux") > -1; //android终端或者uc浏览器
var isiOS = !!u.match(/(i[^;]+;( U;)? CPU.+Mac OS X/); //ios终端
alert("是否是Android："+isAndroid);
alert("是否是iOS："+isiOS);

UserAgent 判断微信客户端

// Mozilla/5.0 (iPhone; CPU iPhone OS 8_3 like Mac OS X) AppleWebKit/600.1.4 (KHTML, like Gecko) Mobile/12F70 MicroMessenger/6.1.5 NetType/WIFI
function isWechat() {  
    var ua = navigator.userAgent.toLowerCase();
    return /micromessenger/i.test(ua) || /windows phone/i.test(ua);
}

JS接口安全域名不填写，分享onMenuShareAppMessage直接会取默认值。

// 分享onMenuShareAppMessage直接会取默认值

关闭当前页面

WeixinJSBridge.call("closeWindow");

支付接口方法调用必须在addevent里边调用

document.addEventListener("WeixinJSBridgeReady", function onBridgeReady(){
    that.initOrder();
}, false);

支付接口方法调用必须在

WeixinJSBridge.invoke("getBrandWCPayRequest", d, function(res){
    if(res.err_msg == "get_brand_wcpay_request:ok"){
        // alert("支付成功");
        // union.release(d.orderId);
        resetUrl();
        paySuccess("home", d.orderId);
    } else {
        cancelOrder(d.orderId);
        // alert(res.err_msg);
    }
    loading.hide();
});

瀑布流无限加载实例

// be dependent on jquery & jquery.infinitescroll.min.js
// insert this "
" to your page.html
(function($){
  $(function(){
      var $container = $(".list-wrap-gd");
      function layOutCallBack() {
          $container.imagesLoaded(function(){
              $container.masonry({
                  itemSelector: ".item-bar",
                  gutter: 10
              });
          });
          $container.imagesLoaded().progress( function() {
              $container.masonry("layout");
          });
      }

      layOutCallBack();

      $container.infinitescroll({
          navSelector : "#more",
          nextSelector : "#more a",
          itemSelector : ".item-bar",
          pixelsFromNavToBottom: 300,
          loading:{
              img: "/images/masonry_loading.gif",
              msgText: " ",
              finishedMsg: "已经到最后一页",
              finished: function(){
                  $("#more").remove();
                  $("#infscr-loading").hide();
              }
          },
          errorCallback:function(){
              $(window).unbind(".infscr");
          },
          pathParse: function (path, nextPage) {
              var query = "";
              var keyword=$("#search_keyword").val();
              var cat_id=$("#cat_id").val();
              var brand_id=$("#brand_id").val();
              var country_id = $("#country_id").val();
              query = query + "&namekeyword="+keyword;
              query = query +"&cat_id="+cat_id
              query = query + "&brand_id=" + brand_id; 
              query = query + "&country_id=" + country_id;
              path = [path,query];
              return path;
          }
      },

      function(newElements) {
          var $newElems = $( newElements ).css({ opacity: 0 });
          $newElems.imagesLoaded(function(){
              $newElems.animate({ opacity: 1 });
              $container.masonry( "appended", $newElems, true );
              layOutCallBack();
          });
      });
  });
})(jQuery);

iOS，Safari浏览器，input等表单focus后fixed元素错位问题

if( /iPhone|iPod|iPad/i.test(navigator.userAgent) ) {
  $(document).on("focus", "input, textarea", function()
  {
     $("header").css("position", "absolute");
     $("footer").css("position", "absolute");
     
  });
  
  $(document).on("blur", "input, textarea", function()
  {
       $("header").css("position", "fixed");
       $("footer").css("position", "fixed");
      
  });
} 

得到地理位置

function getLocation(callback){
  if(navigator.geolocation){
      navigator.geolocation.getCurrentPosition(
              function(p){
                  callback(p.coords.latitude, p.coords.longitude);
              },
              function(e){
                  var msg = e.code + "
" + e.message;
              }
      );
  }
}

rem计算适配

(function(doc, win){
  var docEl = doc.documentElement,
      resizeEvt = "orientationchange" in window ? "orientationchange" : "resize",
      recalc = function(){
          var clientWidth = docEl.clientWidth;
          if(!clientWidth) return;
          docEl.style.fontSize = 20 * (clientWidth / 320) + "px";
      };

  if(!doc.addEventListener) return;
  win.addEventListener(resizeEvt, recalc, false);
  doc.addEventListener("DOMContentLoaded", recalc, false);
})(document, window);

另外一种rem方案

var dpr, rem, scale;
var docEl = document.documentElement;
var fontEl = document.createElement("style");
var metaEl = document.querySelector("meta[name="viewport"]");

dpr = window.devicePixelRatio || 1;
rem = docEl.clientWidth * 2 / 10;
scale = 1 / dpr;


// 设置viewport，进行缩放，达到高清效果
metaEl.setAttribute("content", "width=" + dpr * docEl.clientWidth + ",initial-scale=" + scale + ",maximum-scale=" + scale + ", minimum-scale=" + scale + ",user-scalable=no");

// 设置data-dpr属性，留作的css hack之用
docEl.setAttribute("data-dpr", dpr);

// 动态写入样式
docEl.firstElementChild.appendChild(fontEl);
fontEl.innerHTML = "html{font-size:" + rem + "px!important;}";

// 给js调用的，某一dpr下rem和px之间的转换函数
window.rem2px = function(v) {
    v = parseFloat(v);
    return v * rem;
};
window.px2rem = function(v) {
    v = parseFloat(v);
    return v / rem;
};

window.dpr = dpr;
window.rem = rem;

获取js所在路径

function getJsDir (src) {
    var script = null;

    if (src) {
        script = [].filter.call(document.scripts, function (v) {
            return v.src.indexOf(src) !== -1;
        })[0];
    } else {
        script = document.scripts[document.scripts.length - 1];
    }

    return script ? script.src.substr(0, script.src.lastIndexOf("/")) : script;
}

从全局捕获错误

window.onerror = function (errMsg, scriptURI, lineNumber, columnNumber, errorObj) {
    setTimeout(function () {
        var rst = {
            "错误信息：": errMsg,
            "出错文件：": scriptURI,
            "出错行号：": lineNumber,
            "出错列号：": columnNumber,
            "错误详情：": errorObj
        };

        alert(JSON.stringify(rst, null, 10));
    });
};

字符串长度截取

function cutstr(str, len) {
    var temp,
        icount = 0,
        patrn = /[^x00-xff]/，
        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 + "..."
}

替换全部

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

清除空格

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

清除左空格/右空格

function ltrim(s){ return s.replace( /^(s*|　*)/, ""); } 
function rtrim(s){ return s.replace( /(s*|　*)$/, ""); }

判断是否以某个字符串开头

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

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)
}

转义html标签

function HtmlEncode(text) {
    return text.replace(/&/g, "&").replace(/"/g, """).replace(//g, ">")
}

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
}

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
    }
}

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;"
}

获取cookie值

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

加载样式文件表

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)
    }
}

返回脚本内容

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

清除脚本内容

function stripscript(s) {
    return s.replace(/.*?/ig, "");
}

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) {}
}

返回按ID检索的元素对象

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

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); 
         } 
    }
}

获取当前路径

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

获取页面高度

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

获取页面可视宽度

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

获取页面宽度

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

随机数时间戳

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

日期格式化函数

Date.prototype.format = function(format){
    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 k in 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));
    }
    return format;
}
//调用
//new Date().format("yyyy-MM-dd hh:mm:ss");

返回顶部的通用方法

function backTop(btnId) {
    var btn = document.getElementById(btnId);
    var d = document.documentElement;
    var b = document.body;
    window.onscroll = set;
    btn.style.display = "none";
    btn.onclick = function() {
        btn.style.display = "none";
        window.onscroll = null;
        this.timer = setInterval(function() {
            d.scrollTop -= Math.ceil((d.scrollTop + b.scrollTop) * 0.1);
            b.scrollTop -= Math.ceil((d.scrollTop + b.scrollTop) * 0.1);
            if ((d.scrollTop + b.scrollTop) == 0) clearInterval(btn.timer, window.onscroll = set);
            }, 10);
    };
    function set() {
        btn.style.display = (d.scrollTop + b.scrollTop > 100) ? "block": "none"
    }
};
backTop("goTop");

获得URL中GET参数值

// 用法：如果地址是 test.htm?t1=1&t2=2&t3=3, 那么能取得：GET["t1"], GET["t2"], GET["t3"]
function get_get(){ 
    querystr = window.location.href.split("?")
    if(querystr[1]){
        GETs = querystr[1].split("&");
        GET = [];
        for(i=0;i
数组去重

String.prototype.unique=function(){
    var x=this.split(/[
]+/);
    var y="";
    for(var i=0;i
按字典顺序，对每行进行数组排序

function SetSort(){
    var text=K1.value.split(/[
]/).sort().join("
");//顺序
    var test=K1.value.split(/[
]/).sort().reverse().join("
");//反序
    K1.value=K1.value!=text?text:test;
}
字符串反序输出

function IsReverse(text){
    return text.split("").reverse().join("");
}
金额大写转换函数

//格式转换
function transform(tranvalue) {
    try {
        var i = 1;
        var dw2 = new Array("", "万", "亿"); //大单位
        var dw1 = new Array("拾", "佰", "仟"); //小单位
        var dw = new Array("零", "壹", "贰", "叁", "肆", "伍", "陆", "柒", "捌", "玖"); //整数部分用
        //以下是小写转换成大写显示在合计大写的文本框中     
        //分离整数与小数
        var source = splits(tranvalue);
        var num = source[0];
        var dig = source[1];
        //转换整数部分
        var k1 = 0; //计小单位
        var k2 = 0; //计大单位
        var sum = 0;
        var str = "";
        var len = source[0].length; //整数的长度
        for (i = 1; i <= len; i++) {
              var n = source[0].charAt(len - i); //取得某个位数上的数字
              var bn = 0;
              if (len - i - 1 >= 0) {
                bn = source[0].charAt(len - i - 1); //取得某个位数前一位上的数字
              }
              sum = sum + Number(n);
              if (sum != 0) {
                str = dw[Number(n)].concat(str); //取得该数字对应的大写数字，并插入到str字符串的前面
                if (n == "0") sum = 0;
              }
              if (len - i - 1 >= 0) { //在数字范围内
                if (k1 != 3) { //加小单位
                      if (bn != 0) {
                        str = dw1[k1].concat(str);
                      }
                      k1++;
                } else { //不加小单位，加大单位
                      k1 = 0;
                      var temp = str.charAt(0);
                      if (temp == "万" || temp == "亿") //若大单位前没有数字则舍去大单位
                      str = str.substr(1, str.length - 1);
                      str = dw2[k2].concat(str);
                      sum = 0;
                }
              }
              if (k1 == 3){ //小单位到千则大单位进一
                k2++;
              }
        }
        //转换小数部分
        var strdig = "";
        if (dig != "") {
              var n = dig.charAt(0);
              if (n != 0) {
                strdig += dw[Number(n)] + "角"; //加数字
              }
              var n = dig.charAt(1);
              if (n != 0) {
                strdig += dw[Number(n)] + "分"; //加数字
              }
        }
        str += "元" + strdig;
    } catch(e) {
        return "0元";
    }
    return str;
}
//拆分整数与小数
function splits(tranvalue) {
    var value = new Array("", "");
    temp = tranvalue.split(".");
    for (var i = 0; i < temp.length; i++) {
        value = temp;
    }
    return value;
}