diff --git a/src/highlight.js b/src/highlight.js
index f4f8223a0f..4c9c0658de 100644
--- a/src/highlight.js
+++ b/src/highlight.js
@@ -192,7 +192,7 @@ https://highlightjs.org/
 
     while (original.length || highlighted.length) {
       var stream = selectStream();
-      result += escape(value.substr(processed, stream[0].offset - processed));
+      result += escape(value.substring(processed, stream[0].offset));
       processed = stream[0].offset;
       if (stream === original) {
         /*
@@ -378,7 +378,7 @@ https://highlightjs.org/
       match = top.lexemesRe.exec(mode_buffer);
 
       while (match) {
-        result += escape(mode_buffer.substr(last_index, match.index - last_index));
+        result += escape(mode_buffer.substring(last_index, match.index));
         keyword_match = keywordMatch(top, match);
         if (keyword_match) {
           relevance += keyword_match[1];
@@ -515,7 +515,7 @@ https://highlightjs.org/
         match = top.terminators.exec(value);
         if (!match)
           break;
-        count = processLexeme(value.substr(index, match.index - index), match[0]);
+        count = processLexeme(value.substring(index, match.index), match[0]);
         index = match.index + count;
       }
       processLexeme(value.substr(index));