https://www.bootsfaces.net/jakarta.faces.resource/js/image-loader.…-LGYcp8Y4Rk3fdmMO_kE.systemd-bffront?ln=bsf

1Image.prototype.load = function( url, onLoadStartCallback, onProgressCallback, onLoadEndCallback ) {
2    var thisImg = this,
3        xmlHTTP = new XMLHttpRequest();
4
5    thisImg.completedPercentage = 0;
6
7    xmlHTTP.open( 'GET', url , true );
8    xmlHTTP.responseType = 'arraybuffer';
9
10    xmlHTTP.onload = function( e ) {
11        var h = xmlHTTP.getAllResponseHeaders(),
12            m = h.match( /^Content-Type\:\s*(.*?)$/mi ),
13            mimeType = m[ 1 ] || 'image/png';
14
15        var blob = new Blob( [ this.response ], { type: mimeType } );
16        thisImg.src = window.URL.createObjectURL( blob );
17    };
18
19    xmlHTTP.onprogress = function( e ) {
20        if ( e.lengthComputable )
21            thisImg.completedPercentage = parseInt( ( e.loaded / e.total ) * 100 );
22        if ( onProgressCallback ) onProgressCallback( thisImg );
23    };
24
25    xmlHTTP.onloadstart = function() {
26        thisImg.completedPercentage = 0;
27        if ( onLoadStartCallback ) onLoadStartCallback( thisImg );
28    };
29
30    xmlHTTP.onloadend = function() {
31        thisImg.completedPercentage = 100;
32        if ( onLoadEndCallback ) onLoadEndCallback( thisImg );
33    }
34
35    xmlHTTP.send();
36};