diff --git a/core/modules/widgets/datauri.js b/core/modules/widgets/datauri.js
index ea4d12e81..a7920cf54 100644
--- a/core/modules/widgets/datauri.js
+++ b/core/modules/widgets/datauri.js
@@ -28,8 +28,13 @@ DataUriWidget.prototype.generate = function() {
 	if(tiddler) {
 		var type = tiddler.fields.type || "text/vnd.tiddlywiki",
 			typeInfo = $tw.config.contentTypeInfo[type],
-			isBase64 = typeInfo && typeInfo.encoding === "base64";
-		uri = "data:" + type + (isBase64 ? ";base64" : "") + "," + tiddler.fields.text;
+			isBase64 = typeInfo && typeInfo.encoding === "base64",
+			parts = ["data:"];
+		parts.push(type);
+		parts.push(isBase64 ? ";base64" : "");
+		parts.push(",");
+		parts.push(isBase64 ? tiddler.fields.text : encodeURIComponent(tiddler.fields.text));
+		uri = parts.join("");
 	}
 	// Set the element
 	this.tag = "pre";
@@ -45,4 +50,4 @@ DataUriWidget.prototype.generate = function() {
 
 exports.datauri = DataUriWidget;
 
-})();
+})();
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