make IE download use format:svg and lint

Author: timelyportfolio

src/components/modebar/buttons.js

@@ -49,9 +49,16 @@ modeBarButtons.toImage = {
     title: 'Download plot as a png',
     icon: Icons.camera,
     click: function(gd) {
+        var format = 'png';
+
         Lib.notifier('Taking snapshot - this may take a few seconds', 'long');
 
-        downloadImage(gd)
+        if(Lib.isIE()){
+            Lib.notifier('IE only supports svg.  Changing format to svg.', 'long');
+            format = 'svg';
+        }
+
+        downloadImage(gd, {'format':format})
           .then(function(filename) {
               Lib.notifier('Snapshot succeeded - ' + filename, 'long');
           })

src/snapshot/download.js

@@ -40,7 +40,7 @@ function downloadImage(gd, opts) {
         //   does not allow toDataURL
         //   svg format will work though
         if(Lib.isIE() && opts.format !== 'svg') {
-            reject(new Error('Sorry IE does not support downloading from canvas.'));
+            reject(new Error('Sorry IE does not support downloading from canvas. Try {format:"svg"} instead.'));
         }
 
         gd._snapshotInProgress = true;

src/snapshot/svgtoimg.js

@@ -35,7 +35,7 @@ function svgToImg(opts) {
         // Leave here just in case the CORS/tainted IE issue gets resolved
         if(Lib.isIE()) {
             // replace double quote with single quote
-            svg = svg.replace(/"/gi,"'");
+            svg = svg.replace(/"/gi,'\'');
             // url in svg are single quoted
             //   since we changed double to single
             //   we'll need to change these to double-quoted