Viewport

  

    // meta:
    // <meta content="width=device-width,initial-scale=1, maximum-scale=1, minimum-scale=1, user-scalable=no" name="viewport">

    (function(init_width){
      var isAndroid=navigator.userAgent.match(/(Android)/i)
      , viewPort = document.querySelector("meta[name=viewport]");
      window.html_font_size = isAndroid?100:window.innerWidth*100/init_width;
      
      function setHtmlWidth(){
        document.querySelector("html").style.fontSize = html_font_size + "px";
      }
      
      if (isAndroid) {
        content = "target-densitydpi=320,width="+init_width+",user-scalable=no";
        viewPort.setAttribute("content",content);
      }else{
        setHtmlWidth();window.onresize = setHtmlWidth;
      }
    })(640)

CSS reset

    
    /*css reset*/
    html{font-size:100px}
    body{
      font-size: 0.12rem;
      font-family: "微软雅黑","宋体","arial";
      font-weight: normal;
      overflow-x: hidden;
    }
    body, ul, ol, p, h1, h2, h3, h4, h5, h6, dl, dt, dd ,form ,textarea ,input{margin:0;}
      ul,ol{list-style:none;}
      ul,ol,input{padding:0;}
      table{margin:0 auto;width:100%;border-collapse:collapse;}
      a img{border:0;
    }
    input[type="button"], input[type="submit"], input[type="reset"] {
      -webkit-appearance: none;
    }
    .clearfix:after {
      content: " ";
      display: block;
      clear: both;
      height: 0;
    }
    img{width:100%;}
      .max_width{
      width:6.4rem;
      margin:0 auto;
      position: relative;
    }
    .clear{
      width:100%;
      height:0;
      clear:both;
    }
    .clear30{
      height: 30px;
    }
    .clearfix {
      zoom: 1;
    }
    img,object,audio,vedio{
      max-width: 100%;
    }
    a{
      text-decoration: none;
    }

html


<div class="wrap clearfix">
  <div class="max_width">
  
  </div>
</div>