diff --git a/src/blockview.ts b/src/blockview.ts
index 779a91d0..055b68e4 100644
--- a/src/blockview.ts
+++ b/src/blockview.ts
@@ -97,8 +97,8 @@ export class LineView extends ContentView implements BlockView {
     }
     super.sync(track)
     let last = this.dom!.lastChild
-    if (!last || (last.nodeName != "BR" && (ContentView.get(last) instanceof WidgetView))) {
-      let hack = document.createElement("BR")
+    if (!last || ((last as Element).localName !== "br" && (ContentView.get(last) instanceof WidgetView))) {
+      let hack = document.createElement("br")
       ;(hack as any).cmIgnore = true
       this.dom!.appendChild(hack)
     }
diff --git a/src/buildview.ts b/src/buildview.ts
index c5b5d8e7..78e42aba 100644
--- a/src/buildview.ts
+++ b/src/buildview.ts
@@ -125,5 +125,5 @@ class NullWidget extends WidgetType {
   constructor(readonly tag: string) { super() }
   eq(other: NullWidget) { return other.tag == this.tag }
   toDOM() { return document.createElement(this.tag) }
-  updateDOM(elt: HTMLElement) { return elt.nodeName.toLowerCase() == this.tag }
+  updateDOM(elt: HTMLElement) { return elt.localName === this.tag }
 }
diff --git a/src/cursor.ts b/src/cursor.ts
index 216ae8ce..3aedf348 100644
--- a/src/cursor.ts
+++ b/src/cursor.ts
@@ -181,7 +181,7 @@ function isSuspiciousCaretResult(node: Node, offset: number, x: number) {
   let len
   if (node.nodeType != 3 || offset != (len = node.nodeValue!.length)) return false
   for (let next = node.nextSibling; next; next = node.nextSibling)
-    if (next.nodeType != 1 || next.nodeName != "BR") return false
+    if (next.nodeType != 1 || (next as Element).localName !== "br") return false
   return textRange(node as Text, len - 1, len).getBoundingClientRect().left > x
 }
 
diff --git a/src/dom.ts b/src/dom.ts
index f8da22b2..95433b50 100644
--- a/src/dom.ts
+++ b/src/dom.ts
@@ -57,7 +57,7 @@ function scanFor(node: Node, off: number, targetNode: Node, targetOff: number, d
   for (;;) {
     if (node == targetNode && off == targetOff) return true
     if (off == (dir < 0 ? 0 : maxOffset(node))) {
-      if (node.nodeName == "DIV") return false
+      if ((node as Element).localName === "div") return false
       let parent = node.parentNode
       if (!parent || parent.nodeType != 1) return false
       off = domIndex(node) + (dir < 0 ? 0 : 1)
diff --git a/src/domchange.ts b/src/domchange.ts
index c631107f..bbdb39b2 100644
--- a/src/domchange.ts
+++ b/src/domchange.ts
@@ -155,7 +155,7 @@ class DOMReader {
       if (next == end) break
       let view = ContentView.get(cur), nextView = ContentView.get(next!)
       if ((view ? view.breakAfter : isBlockElement(cur)) ||
-          ((nextView ? nextView.breakAfter : isBlockElement(next!)) && !(cur.nodeName == "BR" && !(cur as any).cmIgnore)))
+          ((nextView ? nextView.breakAfter : isBlockElement(next!)) && !((cur as Element).localName === "br" && !(cur as any).cmIgnore)))
         this.text += this.lineBreak
       cur = next!
     }
@@ -169,7 +169,7 @@ class DOMReader {
     let text: string | undefined
     if (fromView != null) text = fromView.sliceString(0, undefined, this.lineBreak)
     else if (node.nodeType == 3) text = node.nodeValue!
-    else if (node.nodeName == "BR") text = node.nextSibling ? this.lineBreak : ""
+    else if ((node as Element).localName === "br") text = node.nextSibling ? this.lineBreak : ""
     else if (node.nodeType == 1) this.readRange(node.firstChild, null)
 
     if (text != null) {
@@ -196,7 +196,7 @@ class DOMReader {
 }
 
 function isBlockElement(node: Node): boolean {
-  return node.nodeType == 1 && /^(DIV|P|LI|UL|OL|BLOCKQUOTE|DD|DT|H\d|SECTION|PRE)$/.test(node.nodeName)
+  return node.nodeType == 1 && /^(div|p|li|ul|ol|blockquote|dd|dt|h\d|section|pre)$/.test((node as Element).localName)
 }
 
 class DOMPoint {