例：二进制110101转10进制
= 1 * 2^5 + 1 * 2^4 + 0 * 2^3 + 1 * 2^2 + 0 * 2^1 + 1 * 2^0
= 32 + 16 + 0 + 4 + 0 + 1
= 53

例：十进制53转2进制 
= 53/2  = 26 余1
= 26/2  = 3  余0
= 13/2  = 6  余1 
= 6/2   = 3  余0
= 3/2   = 1  余1
= 1/2   = 0  余1 
然后余数倒序 = 110101

input{
 background:#FF9933;
 border–radius:5px;
 color:#fff;
 padding:3px 20px;
–webkit–appearance:none;
}
select{
 background:url(images/img1.jpg) no–repeat;
 background–size:20px;
 background–position:95% center;
 padding:3px 10px;
 width:30%;
–webkit–appearance:none;
}

position: absolute;
left: 50%;
top: 50%;
transform: translate(-50%, -50%);
-webkit-transform:translate(-50%, -50%);

/**
 * v1.1
 * 田丰硕 tianfs.com
 */
(function ($) { 
 $.extend($.fn, { 
 upload: function (settings) { 
 
 var options = $.extend({ 
 fileType: "gif|jpg|jpeg|png|bmp", //允许的文件格式 
 uploadUrl: "", //上传URL地址 
 inputName: "upfile",
 uploadData: {}, //上传时需要附加的参数 可以是 function
 beforeSubmitFn: "", //上传前执行的方法 原型 beforeSubmit(xhr, $this); 
 successFn: "", //上传成功后执行的方法 uploadSuccess(response, statusText, xhr, $this) 
 errorFn: "", //上传失败后执行的方法 
 onProgress:"" //返回上传进度信息
 }, settings); 
 
 //上传准备函数 
 var methods = { 
 //验证文件格式 
 checkFile: function (filename) { 
 var pos = filename.lastIndexOf("."); 
 var str = filename.substring(pos, filename.length); 
 var str1 = str.toLowerCase(); 
 if (typeof options.fileType !== 'string') { options.fileType = "gif|jpg|jpeg|png|bmp"; } 
 var re = new RegExp("\.(" + options.fileType + ")$"); 
 return re.test(str1); 
 }, 
 createInputFile: function(){
 /*var new_fileType = options.fileType.replace(/\|/g,",");
 new_fileType = "."+new_fileType;
 Prompt.topShow(new_fileType)
 var $input = $("<input type='file' name='"+options.inputName+"'> accept='"+new_fileType+"'");*/
 var $input = $("<input type='file' class='upload_tmp_input' style='display:none' name='"+options.inputName+"'> ");
 return $input;
 },
 onload: function () { 
 
 } 
 }; 
 //上传主函数 
 this.each(function () {
 var $this = $(this); 
 $this.bind("click", function () {
 $(".upload_tmp_input").remove()
 //创建input file 
 var $input = methods.createInputFile();
 $this.before($input);
 $input.change(function(){
 if ($input.val() === "") { 
 alert("请选择要上传的文件！"); 
 return false; 
 } 
 //验证图片 
 if (!methods.checkFile($input.val())) {
 alert("文件格式不正确，只能上传格式为：" + options.fileType + "的文件。"); 
 return false; 
 }
 var pic = $input.get(0).files[0];
 var formData = new FormData();
 formData.append(options.inputName , pic);
 if (typeof options.uploadData == 'function') {
 var data = options.uploadData($this);
 if (data) {
 for (var x in data) {
 formData.append(x , data[x]);
 }
 }
 } else {
 if (options.uploadData) {
 for (var x in options.uploadData) {
 formData.append(x , options.uploadData[x]);
 }
 }
 }
 /** 
 * 必须false才会避开jQuery对 formdata 的默认处理 
 * XMLHttpRequest会对 formdata 进行正确的处理 
 */ 
 $.ajax({
 type: "POST",
 url: options.uploadUrl,
 data: formData ,
 processData : false, 
 //必须false才会自动加上正确的Content-Type 
 contentType : false ,
 dataType : "JSON",
 xhr: function(){
 var xhr = $.ajaxSettings.xhr();
 xhr.upload.addEventListener("progress" , function (evt){
 console.log(evt);
 var loaded = evt.loaded; //已经上传大小情况 
 var tot = evt.total; //附件总大小 
 var per = Math.floor(100*loaded/tot); //已经上传的百分比 
 var onProgress; 
 try { onProgress = eval(options.onProgress) } catch (err) { }; 
 if (onProgress) { 
 onProgress(per, $this); 
 } 
 }, false);
 return xhr;
 },
 beforeSend:function (xhr) {
 $this.attr("disabled", true);
 var beforeSubmitFn; 
 try { beforeSubmitFn = eval(options.beforeSubmitFn) } catch (err) { }; 
 if (beforeSubmitFn) { 
 var $result = beforeSubmitFn(xhr, $this); 
 if (typeof ($result) == "boolean") 
 return $result; 
 } 
 },
 error : function (response, statusText, xhr) { 
 var errorFn; 
 try { errorFn = eval(options.errorFn) } catch (err) { }; 
 if (errorFn) { 
 errorFn(response, statusText, xhr, $this); 
 }
 $this.attr("disabled", false); 
 $input.remove(); 
 },
 //上传成功 
 success : function (response, statusText, xhr) { 
 //response = eval("(" + response + ")"); 
 var successFn; 
 try { successFn = eval(options.successFn) } catch (err) { }; 
 if (successFn) { 
 $.ajaxSetup({ cache: false });//这个不能少，否则ie下会提示下载 
 successFn(response, statusText, xhr, $this); 
 } 
 $this.attr("disabled", false); 
 $input.remove(); 
 }
 
 });
 })
 $input.click()
 }); 
 
 }); 
 } 
 }); 
})(jQuery)

$(“.upload-quan”).upload({
uploadData: {},
uploadUrl : “”,
inputName: “upfile”,
fileType: “bmp|png|jpeg|jpg|gif”,
successFn: function (response, statusText, xhr, $this) {
console.log(response);
}
});

.page{
    width:960px;
    height:1000px;
    margin:0 auto;
    background:#CCC;
}
/* 设备最大宽度960px */
@media screen and (max–width: 960px) {
    .page{
        width:100%;
        background:#69F;
    }
}
/* 宽度大于480px且小于768px */
@media screen and (min–width: 480px) and (max–width:768px) {
    .page{
        width:100%;
        background:#F00;
    }
}
/* 设备最大宽度480px */
@media screen and (max–width:480px){
    .page{
        width:100%;
        background:#00FF00;
    }
}

 下方是运算
  00101 
& 11100 
------------ 
  00100

$ hexo server

下方回显
 1 & 5 = 1
 2 & 5 = 0
 4 & 5 = 4
 8 & 5 = 0

<!DOCTYPE html> 
<html lang="en"> 
<head> 
  <meta charset="UTF-8"> 
  <title>Checkbox Test</title> 
</head> 
<body> 
<form> 
  <input type="checkbox" name="test" value="1"> 1 
  <input type="checkbox" name="test" value="2"> 2 
  <input type="checkbox" name="test" value="4"> 4 
  <input type="checkbox" name="test" value="8"> 8 
</form> 
<input type="text" id="result" placeholder="设置要回显的值"> 
<button id="show">回显</button> 
<script src="http://libs.baidu.com/jquery/1.11.1/jquery.min.js"></script> 
<script> 
$(function () { 
  $("[name='test']").on("change", function () { 
    var result = 0; 
    $("[name='test']:checkbox:checked").each(function(){ 
      result += parseInt($(this).val()); 
    }); 
    $("#result").val(result); }); 
    $("#show").on("click", function () { 
      var result = parseInt($("#result").val()); 
      $("[name='test']:checkbox").each(function(){ 
        var value = parseInt($(this).val()); 
        if ((result & value) == value) { 
        $(this).prop("checked", true); 
        } else { 
        $(this).prop("checked", false); 
        } 
      }); 
   }); 
}); 
</script> 
</body> 
</html>