JavaScript Asynchronous Download Promise implementation

General download is directly open a link on the line.
var URL = ' XXXX ';
window.open (URL)
In fact, this will have some problems:
1. The browser prohibits opening a new window, resulting in the inability to download

So how to solve it?
Such

1 <  href= "http://somehost/somefile.zip"  download= "Filename.zip"  >Download file</a>

Note the Download property, which describes the download, and the file name: Filename.zip

So how to download asynchronously?
JS Code:

1 varMydownload =function(){};2Mydownload.prototype = {3      //sync Download, just turn the above example into JS4Downloadfunction(URL, filename) {5         varA = document.createelement (' A ');6A.href =URL;7A.download =filename;8 A.click ();9     },Ten  One     //according to the Blob object to download ADownloadbyblob:function(blod,name) { -Console.log (' Blod ', Blod); -Name = Name | |Blod.name; the         varFileURL = window. Url.createobjecturl (Blod);//Convert to an accessible URL -          This. Download (FileURL, name);//Download -Window. Url.revokeobjecturl (FileURL);//release URL after download -     }, +  -     //asynchronous Data= ' name=mynam&age=20 ' +Ajax:function(URL,DATA,METHOD,TYPE,SUCCESSFUC,ERRORFUC) { AMethod = Method | | ' GET '; atdata = Data | | ‘‘; -Type = Type | | ' Blob '; -         varRequest =NewXMLHttpRequest (); -         if(window. XMLHttpRequest) { -request=NewXMLHttpRequest (); -         } in         Else if(window. ActiveXObject) { -request=NewActiveXObject ("Microsoft.XMLHTTP"); to}Else{ +             return false; -         } the Request.open (method, url); *Request.responsetype =type; $         //When the request loads, check whether it is successfulPanax NotoginsengRequest.onload =function() { -             if(Request.status = = 200) { the                 if(SUCCESSFUC) { +                     varfilename = Request.getresponseheader (' content-disposition '); A                     if(filename) { the                         varindex = filename.indexof (' filename= '); +                         if(Index!==-1){ -filename = filename.substring (index+9); $                         } $                     } - successfuc (request.response,filename) -                 } the}Else { -                 if(SUCCESSFUC) {Wuyi successfuc (request.response) the                 } -             } Wu         } -Request.onerror =function(Error) { About         //Also deal with the case, the entire request fails to begin with $         //This is probably a network error, so reject the promise with an appropriate message -             if(ERRORFUC) { - errorfuc (error.response) -             } A         }; +         //Send the request theRequest.setrequestheader ("Content-type", "application/x-www-form-urlencoded"); - request.send (data); $     }, the  the     //Asynchronous Download No promise theDownloadasync:function(url,name,data,method) { the         varSelf = This; -          This. Ajax (Url,data,method, ' blob ',function(blob,filename) { inSelf.downloadbyblob (blob,name| |filename); the         }); the     }, About  the     //asynchronous download using Promise theDownloadpromise:function(url,name,data,method) { the         if(window. Promise) { +             varSelf = This; -             return NewPromise (function(Resolve, reject) { theConsole.log ( This, ' this ');BayiSelf.ajax (Url,data,method, ' blob ',function(response,filename) { the Resolve ({ the Data:response, - Filename:filename -                     }); the},function(response,filename) { the reject ({ the Data:response, the Filename:filename -                     }); the                 }) the}). Then (function(JSON) { the Self.downloadbyblob (json.data,json.filename);94             });; the}Else{ the Self.downloadasync (url,data,method); the         }98     } About}

Code for PHP:

1 Ini_set(' Memory_limit ', ' 64M ');2 $file= "Mylittlevader.jpg";3 Header(' Content-type:application/octet-stream ');4 Header(' Content-disposition:attachment; Filename= '.$file);//Set file name5 Header(' Content-length: '.filesize($file));6 ReadFile($file);

Html:

1 <!DOCTYPE HTML>2 <HTML>3   <Head>4     <MetaCharSet= "Utf-8">5     <Metahttp-equiv= "X-ua-compatible"content= "Ie=edge,chrome=1">6     <Metaname= "Viewport"content= "Width=device-width">7 8     <title>Asynchronous Download Example</title>9   </Head>Ten  One   <Body> A     <H1>Asynchronous Download Example</H1> -     <ahref="#"onclick= ' Downjs.downloadpromise ("download.php") '>Downloadjs</a> -   </Body> the  - <Scripttype= "Text/javascript"src= "./download.js"></Script> -   <Script> -   varDownjs= Newmydownload (); +   </Script> - </HTML>

The general use of download can be both, can directly:

1 downjs.download (URL)

Reference:
1190000005863250
Promise Download

JavaScript Asynchronous Download Promise implementation