addSizes.js 自定标注链接文件的大小

addSizes.js 自定标注链接文件的大小

addSizes.js 是一段 JS 代码 , 用于从一个页面里链接的一些大的文件 , 并自动在它们的链接旁边标注文件大小。它的作者是 Nathalie Downe ，应用了 Simon Willison 的 json-head App Engine 迷你服务。

使用它，你的链接不需要额外的代码，它自动会在页面里找到你的链接并更改为这样的格式，如 ” 你的链接 (pdf 2.8 MB)” 。的确很好用！



JAVASCRIPT:



jQuery( function ($) {



    $( 'a[href$=".pdf"], a[href$=".doc"], a[href$=".mp3"], a[href$=".m4u"]' ).each( function () {

         // looking at the href of the link, if it contains .pdf or .doc or .mp3

         var link = $( this );

         var bits = this .href.split( '.' );

         var type = bits[bits.length -1];

              

         var url= "http://json-head.appspot.com/?url=" +encodeURI($( this ).attr( 'href' ))+ "&callback=?" ;



         // then call the json thing and insert the size back into the link text

         $.getJSON(url, function (json) {

                if (json.ok && json.headers[ 'Content-Length' ]) {

                        var length = parseInt(json.headers[ 'Content-Length' ], 10);



                        // divide the length into its largest unit

                        var units = [

                              [1024 * 1024 * 1024, 'GB' ],

                              [1024 * 1024, 'MB' ],

                              [1024, 'KB' ],

                              [1, 'bytes' ]

                         ];



                         for ( var i = 0; i <units.length; i++) {



                               var unitSize = units[i][0];

                               var unitText = units[i][1];



                               if (length>= unitSize) {

                                       length = length / unitSize;

                                       // 1 decimal place

                                       length = Math.ceil(length * 10) / 10;

                                       var lengthUnits = unitText;

                                        break ;

                               }

                         }

                          // insert the text directly after the link and add a class to the link

                         link.after( ' (' + type + ' ' + length + ' ' + lengthUnits + ')' );

                         link.addClass(type);

                     }

           } );

     } );

} );