diff --git a/beautify.js b/beautify.js
index 157692d7..c4955d25 100755
--- a/beautify.js
+++ b/beautify.js
@@ -531,7 +531,7 @@ function js_beautify(js_source_text, options) {
                     //
                     while (esc || input.charAt(parser_pos) !== sep) {
                         resulting_string += input.charAt(parser_pos);
-                        if (esc1 >= esc2) {
+                        if (esc1 && esc1 >= esc2) {
                             esc1 = parseInt(resulting_string.substr(-esc2), 16);
                             if (esc1 && esc1 >= 0x20 && esc1 <= 0x7e) {
                                 esc1 = String.fromCharCode(esc1);
diff --git a/php/jsbeautifier.php b/php/jsbeautifier.php
index 189d7658..1b8855c9 100644
--- a/php/jsbeautifier.php
+++ b/php/jsbeautifier.php
@@ -629,11 +629,11 @@ class JSBeautifier
 					while ($esc || $this->input[$this->parser_pos] != $sep) {
 						$resulting_string .= $this->input[$this->parser_pos];
 
-						if ($esc1 >= $esc2) {
+						if ($esc1 && $esc1 >= $esc2) {
 							$esc1 = hexdec(substr($resulting_string, -$esc2));
 							if ($esc1 && $esc1 >= 0x20 && $esc1 <= 0x7e) {
 								$esc1 = chr($esc1);
-								$resulting_string = substr($resulting_string, 0, -($esc2 + 2)) . ((($esc1 === $sep) || ($esc1 === '\\')) ? '\\' : '') . $esc1;
+								$resulting_string = substr($resulting_string, 0, -2 - $esc2) . ((($esc1 === $sep) || ($esc1 === '\\')) ? '\\' : '') . $esc1;
 							}
 							$esc1 = 0;
 						}
diff --git a/python/jsbeautifier/__init__.py b/python/jsbeautifier/__init__.py
index bfa2d344..1d3b825e 100644
--- a/python/jsbeautifier/__init__.py
+++ b/python/jsbeautifier/__init__.py
@@ -557,7 +557,7 @@ class Beautifier:
                     # handle string
                     while esc or self.input[parser_pos] != sep:
                         resulting_string += self.input[parser_pos]
-                        if esc1 >= esc2:
+                        if esc1 and esc1 >= esc2:
                             try:
                                 esc1 = int(resulting_string[-esc2:], 16)
                             except Exception: