diff --git a/autoload/emmet.vim b/autoload/emmet.vim
index 84a914a..f9c77e5 100644
--- a/autoload/emmet.vim
+++ b/autoload/emmet.vim
@@ -1,7 +1,7 @@
 "=============================================================================
 " emmet.vim
 " Author: Yasuhiro Matsumoto <mattn.jp@gmail.com>
-" Last Change: 06-Aug-2013.
+" Last Change: 08-Aug-2013.
 
 let s:save_cpo = &cpo
 set cpo&vim
@@ -199,7 +199,11 @@ function! emmet#toString(...)
           let text = current.value[1:-2]
           if dollar_expr
             " TODO: regexp engine specified
-            let text = substitute(text, '\%#=1\%(\\\)\@\<!\(\$\+\)\([^{#]\|$\)', '\=printf("%0".len(submatch(1))."d", max([itemno, group_itemno])+1).submatch(2)', 'g')
+            if exists('&regexpengine')
+              let text = substitute(text, '\%#=1\%(\\\)\@\<!\(\$\+\)\([^{#]\|$\)', '\=printf("%0".len(submatch(1))."d", max([itemno, group_itemno])+1).submatch(2)', 'g')
+            else
+              let text = substitute(text, '\%(\\\)\@\<!\(\$\+\)\([^{#]\|$\)', '\=printf("%0".len(submatch(1))."d", max([itemno, group_itemno])+1).submatch(2)', 'g')
+            endif
             let text = substitute(text, '\${nr}', "\n", 'g')
             let text = substitute(text, '\\\$', '$', 'g')
           endif
diff --git a/autoload/emmet/lang/html.vim b/autoload/emmet/lang/html.vim
index ce88dbf..382767a 100644
--- a/autoload/emmet/lang/html.vim
+++ b/autoload/emmet/lang/html.vim
@@ -333,7 +333,11 @@ function! emmet#lang#html#toString(settings, current, type, inline, filters, ite
     let text = current.value[1:-2]
     if dollar_expr
       " TODO: regexp engine specified
-      let text = substitute(text, '\%#=1\%(\\\)\@\<!\(\$\+\)\([^{#]\|$\)', '\=printf("%0".len(submatch(1))."d", itemno+1).submatch(2)', 'g')
+      if exists('&regexpengine')
+        let text = substitute(text, '\%#=1\%(\\\)\@\<!\(\$\+\)\([^{#]\|$\)', '\=printf("%0".len(submatch(1))."d", itemno+1).submatch(2)', 'g')
+      else
+        let text = substitute(text, '\%(\\\)\@\<!\(\$\+\)\([^{#]\|$\)', '\=printf("%0".len(submatch(1))."d", itemno+1).submatch(2)', 'g')
+      endif
       let text = substitute(text, '\${nr}', "\n", 'g')
       let text = substitute(text, '\\\$', '$', 'g')
     endif
@@ -349,7 +353,11 @@ function! emmet#lang#html#toString(settings, current, type, inline, filters, ite
     if dollar_expr
       while val =~ '\$\([^#{]\|$\)'
         " TODO: regexp engine specified
-        let val = substitute(val, '\%#=1\(\$\+\)\([^{#]\|$\)', '\=printf("%0".len(submatch(1))."d", itemno+1).submatch(2)', 'g')
+        if exists('&regexpengine')
+          let val = substitute(val, '\%#=1\(\$\+\)\([^{#]\|$\)', '\=printf("%0".len(submatch(1))."d", itemno+1).submatch(2)', 'g')
+        else
+          let val = substitute(val, '\(\$\+\)\([^{#]\|$\)', '\=printf("%0".len(submatch(1))."d", itemno+1).submatch(2)', 'g')
+        endif
       endwhile
       let attr = substitute(attr, '\$$', itemno+1, '')
     endif
@@ -369,7 +377,11 @@ function! emmet#lang#html#toString(settings, current, type, inline, filters, ite
     let text = current.value[1:-2]
     if dollar_expr
       " TODO: regexp engine specified
-      let text = substitute(text, '\%#=1\%(\\\)\@\<!\(\$\+\)\([^{#]\|$\)', '\=printf("%0".len(submatch(1))."d", itemno+1).submatch(2)', 'g')
+      if exists('&regexpengine')
+        let text = substitute(text, '\%#=1\%(\\\)\@\<!\(\$\+\)\([^{#]\|$\)', '\=printf("%0".len(submatch(1))."d", itemno+1).submatch(2)', 'g')
+      else
+        let text = substitute(text, '\%(\\\)\@\<!\(\$\+\)\([^{#]\|$\)', '\=printf("%0".len(submatch(1))."d", itemno+1).submatch(2)', 'g')
+      endif
       let text = substitute(text, '\${nr}', "\n", 'g')
       let text = substitute(text, '\\\$', '$', 'g')
       let str = substitute(str, '\("\zs$#\ze"\|\s\zs\$#"\|"\$#\ze\s\)', text, 'g')