js常用函数记录

1、js实用方法记录-动态加载css/js

/**
     * 动态加载css
     * @param {string} url 样式地址
     */
    function dynamicloadcss(url) {
        var head = document.getelementsbytagname('head')[0];
        var link = document.createelement('link');
        link.type='text/css';
        link.rel = 'stylesheet';
        link.href = url;
        head.appendchild(link);
    }

/**
     * 动态加载css脚本
     * @param {string} csstext css样式
     */
    function loadstylestring(csstext) {
        var style = document.createelement("style");
        style.type = "text/css";
        try{
            // firefox、safari、chrome和opera
            style.appendchild(document.createtextnode(csstext));
        }catch(ex) {
            // ie早期的浏览器 ,需要使用style元素的stylesheet属性的csstext属性
            style.stylesheet.csstext = csstext;
        }
        document.getelementsbytagname("head")[0].appendchild(style);
    }

    // 测试
    var css = "body{color:blue;}";
    loadstylestring(css);

 /**
     * 动态加载js脚本
     * @param {string} code js脚本
     */
    function loadscriptstring(code) {
        var script = document.createelement("script");
        script.type = "text/javascript";
        try{
            // firefox、safari、chrome和opera
            script.appendchild(document.createtextnode(code));
        }catch(ex) {
            // ie早期的浏览器 ,需要使用script的text属性来指定javascript代码。
            script.text = code;
        }
        document.getelementsbytagname("head")[0].appendchild(script);
    }
    // 测试
    var text = "function test(){alert('test');}";
    loadscriptstring(text);
    test();

/**
   * 动态加载iframe
   * @param {string} url 脚本地址
   * @param {function} callback  回调函数
   * @param {string} style  加载样式
   */
  function dynamicloadiframe(url,callback,style) {
    var body = document.getelementsbytagname('body')[0];
    var iframe = document.createelement('iframe');
    iframe.src = url;
    iframe.style=style||'display:none;width:0px;height:0px;';
    if(typeof(callback)=='function'){
        iframe.onload = iframe.onreadystatechange = function () {
            if (!this.readystate || this.readystate === "loaded" || this.readystate === "complete") {
                callback();
                iframe.onload = iframe.onreadystatechange = null;
            }
        };
    }
    body.appendchild(iframe);
  }

//方法测试：openapp('ios页面','**.apk','metools://home');

function openapp(iosdownurl,anddownurl,appurl) {
    var ua = navigator.useragent.tolowercase();    
    if (/iphone|ipad|ipod/.test(ua)) {//ios跳转到store
      window.location.href = iosdownurl;
      return;
    } 
    if(ua.indexof("micromessenger") > -1){//微信中不能打开其他app
      window.location.href = anddownurl;
      return;
    }
    if (/android/.test(ua)) {//安卓手机尝试调用app
      if(!appurl){
        console.log('未指定需要打开的app,可参考https://www.oschina.net/code/snippet_256033_35330/');
        return;
      }
      var su = appurl;//"metools://index";//自定义协议
      var n = settimeout(function () {
        window.location.href = anddownurl
      }, 500);
      var r = document.createelement("iframe");
      r.src = su;
      r.onload = function () {
        console.log('iframe load')
        cleartimeout(n);
        r.parentnode.removechild(r);
        window.location.href = su;
      };
      r.setattribute("style", "display:none;");
      document.body.appendchild(r);
      return;
    }
    window.location.href = anddownurl;
  }

/**
     * 动态加载js
     * @param {string} url 脚本地址
     * @param {function} callback  回调函数
     */
    function dynamicloadjs(url, callback) {
        var head = document.getelementsbytagname('head')[0];
        var script = document.createelement('script');
        script.type = 'text/javascript';
        script.src = url;
        if(typeof(callback)=='function'){
            script.onload = script.onreadystatechange = function () {
                if (!this.readystate || this.readystate === "loaded" || this.readystate === "complete"){
                    callback();
                    script.onload = script.onreadystatechange = null;
                }
            };
        }
        head.appendchild(script);
    }
//方法调用：dynamicloadjs('https://www.yimo.link/static/js/main.min.js',function(){alert('加载成功')});

2、检测到是移动端还是pc端进入页面，加载不同样式表现

//第一种方式：
if(/applewebkit.*mobile/i.test(navigator.useragent) || (/midp|symbianos|nokia|samsung|lg|nec|tcl|alcatel|bird|dbtel|dopod|philips|haier|lenovo|mot-|nokia|sonyericsson|sie-|amoi|zte/.test(navigator.useragent))) {
                if(window.location.href.indexof("mobile") < 0) {
                    try {
                        if(/android|webos|iphone|ipod|blackberry/i.test(navigator.useragent)) {
                            //window.location.href = "手机页面";
                            console.log('手机页面')
                        } else if(/ipad/i.test(navigator.useragent)) {
                            //window.location.href = "平板页面";
                            console.log('平板页面')
                        } else {
                            //window.location.href = "其他移动端页面"
                            console.log('其他移动端页面')
                        }
                    } catch(e) {}
                }
            }else{
                console.log('pc页面');
            }
//第二种方式：
<script type="text/javascript">
            // 判断是否为移动端运行环境 
            if(/applewebkit.*mobile/i.test(navigator.useragent) || (/midp|symbianos|nokia|samsung|lg|nec|tcl|alcatel|bird|dbtel|dopod|philips|haier|lenovo|mot-|nokia|sonyericsson|sie-|amoi|zte/.test(navigator.useragent))) {
                if(window.location.href.indexof("mobile") ");
            }
        </script>
//第三种方式：
window.location.href = /android|webos|iphone|ipod|blackberry/i.test(navigator.useragent)  "https://www.baidu.com/" :  "https://news.baidu.com/";



if(/android|webos|iphone|ipod|blackberry/i.test(navigator.useragent)) {
    window.location.href = "https://www.baidu.com/";
} else {
    window.location.href = "https://news.baidu.com/";
}