diff --git a/ts/adaptors/jsdomAdaptor.ts b/ts/adaptors/jsdomAdaptor.ts
index d41e6d5b5..d22ca6ca4 100644
--- a/ts/adaptors/jsdomAdaptor.ts
+++ b/ts/adaptors/jsdomAdaptor.ts
@@ -30,6 +30,8 @@ export class JsdomAdaptor extends HTMLAdaptor<HTMLElement, Text, Document> {
    * The default options
    */
   public static OPTIONS: OptionList = {
+    fontSize: 16,          // We can't compute the font size, so always use this
+    fontFamily: 'Times',   // We can't compute the font family, so always use this
     cjkCharWidth: 1,       // Width (in em units) of full width characters
     unknownCharWidth: .6,  // Width (in em units) of unknown (non-full-width) characters
     unknownCharHeight: .8, // Height (in em units) of unknown characters
@@ -74,6 +76,32 @@ export class JsdomAdaptor extends HTMLAdaptor<HTMLElement, Text, Document> {
     this.options = userOptions(defaultOptions({}, CLASS.OPTIONS), options);
   }
 
+  /**
+   * JSDOM's getComputedStyle() implementation is badly broken, and only
+   *   return the styles explicitly set on the given node, not the
+   *   inherited values frmo the cascading style sheets (so it is pretty
+   *   useless).  This is somethig we can't really work around, so use
+   *   the default value given in the options instead.  Sigh
+   *
+   * @override
+   */
+  public fontSize(_node: HTMLElement) {
+    return this.options.fontSize;
+  }
+
+  /**
+   * JSDOM's getComputedStyle() implementation is badly broken, and only
+   *   return the styles explicitly set on the given node, not the
+   *   inherited values frmo the cascading style sheets (so it is pretty
+   *   useless).  This is somethig we can't really work around, so use
+   *   the default value given in the options instead.  Sigh
+   *
+   * @override
+   */
+  public fontFamily(_node: HTMLElement) {
+    return this.options.fontFamily;
+  }
+
   /**
    * @override
    */
diff --git a/ts/output/common/OutputJax.ts b/ts/output/common/OutputJax.ts
index 98ff83cb7..1900c49e3 100644
--- a/ts/output/common/OutputJax.ts
+++ b/ts/output/common/OutputJax.ts
@@ -423,8 +423,9 @@ export abstract class CommonOutputJax<
     const adaptor = this.adaptor;
     const family = (getFamily ? adaptor.fontFamily(node) : '');
     const em = adaptor.fontSize(node);
-    const ex = (adaptor.nodeSize(adaptor.childNode(node, 1) as N)[1] / 60) || (em * this.options.exFactor);
-    const containerWidth = (adaptor.getStyle(node, 'display') === 'table' ?
+    const [w, h] = adaptor.nodeSize(adaptor.childNode(node, 1) as N);
+    const ex = (w ? h / 60 : em * this.options.exFactor);
+    const containerWidth = (!w ? 1000000 : adaptor.getStyle(node, 'display') === 'table' ?
                             adaptor.nodeSize(adaptor.lastChild(node) as N)[0] - 1 :
                             adaptor.nodeBBox(adaptor.lastChild(node) as N).left -
                             adaptor.nodeBBox(adaptor.firstChild(node) as N).left - 2);