jQuery之$.support.xxx

下面这段代码来自jQuery-file-upload 9.19官方Demo

 $(function () {
     'use strict';
     // Change this to the location of your server-side upload handler:
     var url = window.location.hostname === 'blueimp.github.io' ?
                 '//jquery-file-upload.appspot.com/' : 'server/php/';
     $('#fileupload').fileupload({
         url: url,
         dataType: 'json',
         done: function (e, data) {
             $.each(data.result.files, function (index, file) {
                 $('<p/>').text(file.name).appendTo('#files');
             });
         },
         progressall: function (e, data) {
             var progress = parseInt(data.loaded / data.total * 100, 10);
             $('#progress .progress-bar').css(
                 'width',
                 progress + '%'
             );
         }
     }).prop('disabled', !$.support.fileInput)
         .parent().addClass($.support.fileInput ? undefined : 'disabled');
 });

对应的HTML

<input id="fileupload" type="file" name="files[]" multiple>

jQuery.support 用于检查浏览器对各项特性的支持。检查项多达 27 个。经搜索,应该是时从jQuery 1.9 开始.

w3school参考

注意这里的字面值"fileInput",fileupload插件可以使用input标签的id值作为属性名指引所生成的jquery插件对象, 此编程模式待学习研究.