diff --git a/application/helpers/expressions/em_core_helper.php b/application/helpers/expressions/em_core_helper.php
index 4b2ac0f7a2d..83e1661d697 100644
--- a/application/helpers/expressions/em_core_helper.php
+++ b/application/helpers/expressions/em_core_helper.php
@@ -213,17 +213,17 @@ function __construct()
 'strcasecmp' => array('strcasecmp', 'strcasecmp', gT('Binary safe case-insensitive string comparison'), 'int strcasecmp(str1, str2)', 'http://www.php.net/manual/en/function.strcasecmp.php', 2),
 'strcmp' => array('strcmp', 'strcmp', gT('Binary safe string comparison'), 'int strcmp(str1, str2)', 'http://www.php.net/manual/en/function.strcmp.php', 2),
 'strip_tags' => array('strip_tags', 'strip_tags', gT('Strip HTML and PHP tags from a string'), 'string strip_tags(str, allowable_tags)', 'http://www.php.net/manual/en/function.strip-tags.php', 1,2),
-'stripos' => array('stripos', 'stripos', gT('Find position of first occurrence of a case-insensitive string'), 'int stripos(haystack, needle [, offset=0])', 'http://www.php.net/manual/en/function.stripos.php', 2,3),
+'stripos' => array('exprmgr_stripos', 'stripos', gT('Find position of first occurrence of a case-insensitive string'), 'int stripos(haystack, needle [, offset=0])', 'http://www.php.net/manual/en/function.stripos.php', 2,3),
 'stripslashes' => array('stripslashes', 'stripslashes', gT('Un-quotes a quoted string'), 'string stripslashes(string)', 'http://www.php.net/manual/en/function.stripslashes.php', 1),
-'stristr' => array('stristr', 'stristr', gT('Case-insensitive strstr'), 'string stristr(haystack, needle [, before_needle=false])', 'http://www.php.net/manual/en/function.stristr.php', 2,3),
-'strlen' => array('strlen', 'LEMstrlen', gT('Get string length'), 'int strlen(string)', 'http://www.php.net/manual/en/function.strlen.php', 1),
-'strpos' => array('strpos', 'LEMstrpos', gT('Find position of first occurrence of a string'), 'int strpos(haystack, needle [ offset=0])', 'http://www.php.net/manual/en/function.strpos.php', 2,3),
+'stristr' => array('exprmgr_stristr', 'stristr', gT('Case-insensitive strstr'), 'string stristr(haystack, needle [, before_needle=false])', 'http://www.php.net/manual/en/function.stristr.php', 2,3),
+'strlen' => array('exprmgr_strlen', 'LEMstrlen', gT('Get string length'), 'int strlen(string)', 'http://www.php.net/manual/en/function.strlen.php', 1),
+'strpos' => array('exprmgr_strpos', 'LEMstrpos', gT('Find position of first occurrence of a string'), 'int strpos(haystack, needle [ offset=0])', 'http://www.php.net/manual/en/function.strpos.php', 2,3),
 'strrev' => array('strrev', 'strrev', gT('Reverse a string'), 'string strrev(string)', 'http://www.php.net/manual/en/function.strrev.php', 1),
-'strstr' => array('strstr', 'strstr', gT('Find first occurrence of a string'), 'string strstr(haystack, needle)', 'http://www.php.net/manual/en/function.strstr.php', 2),
-'strtolower' => array('strtolower', 'LEMstrtolower', gT('Make a string lowercase'), 'string strtolower(string)', 'http://www.php.net/manual/en/function.strtolower.php', 1),
+'strstr' => array('exprmgr_strstr', 'strstr', gT('Find first occurrence of a string'), 'string strstr(haystack, needle [, before_needle=false])', 'http://www.php.net/manual/en/function.strstr.php', 2,3),
+'strtolower' => array('exprmgr_strtolower', 'LEMstrtolower', gT('Make a string lowercase'), 'string strtolower(string)', 'http://www.php.net/manual/en/function.strtolower.php', 1),
 'strtotime' => array('strtotime', 'strtotime', gT('Convert a date/time string to unix timestamp'), 'int strtotime(string)', 'http://www.php.net/manual/de/function.strtotime.php', 1),
-'strtoupper' => array('strtoupper', 'LEMstrtoupper', gT('Make a string uppercase'), 'string strtoupper(string)', 'http://www.php.net/manual/en/function.strtoupper.php', 1),
-'substr' => array('substr', 'substr', gT('Return part of a string'), 'string substr(string, start [, length])', 'http://www.php.net/manual/en/function.substr.php', 2,3),
+'strtoupper' => array('exprmgr_strtoupper', 'LEMstrtoupper', gT('Make a string uppercase'), 'string strtoupper(string)', 'http://www.php.net/manual/en/function.strtoupper.php', 1),
+'substr' => array('exprmgr_substr', 'substr', gT('Return part of a string'), 'string substr(string, start [, length])', 'http://www.php.net/manual/en/function.substr.php', 2,3),
 'sum' => array('array_sum', 'LEMsum', gT('Calculate the sum of values in an array'), 'number sum(arg1, arg2, ... argN)', '', -2),
 'sumifop' => array('exprmgr_sumifop', 'LEMsumifop', gT('Sum the values of answered questions in the list which pass the critiera (arg op value)'), 'number sumifop(op, value, arg1, arg2, ... argN)', '', -3),
 'tan' => array('tan', 'Math.tan', gT('Tangent'), 'number tan(arg)', 'http://www.php.net/manual/en/function.tan.php', 1),
@@ -2538,7 +2538,88 @@ function exprmgr_countifop($args)
     }
     return $j;
 }
-
+/**
+ * Find position of first occurrence of unicode string in a unicode string, case insensitive
+ * @param string $haystack : checked string
+ * @param string $needle : string to find
+ * @param $offset : offset
+ * @return int|false : position or false if not found
+ */
+function exprmgr_stripos($haystack , $needle ,$offset=0)
+{
+    return mb_stripos($haystack , $needle ,$offset,'UTF-8');
+}
+/**
+ * Finds first occurrence of a unicode string within another, case-insensitive
+ * @param string $haystack : checked string
+ * @param string $needle : string to find
+ * @param boolean $before_needle : portion to return
+ * @return string|false 
+ */
+function exprmgr_stristr($haystack,$needle,$before_needle=false)
+{
+    return mb_stristr($haystack,$needle,$before_needle,'UTF-8');
+}
+/**
+ * Get unicode string length 
+ * @param string $string
+ * @return int
+ */
+function exprmgr_strlen($string)
+{
+    return mb_strlen ($string,'UTF-8');
+}
+/**
+ * Find position of first occurrence of unicode string in a unicode string
+ * @param string $haystack : checked string
+ * @param string $needle : string to find
+ * @param $offset : offset
+ * @return int|false : position or false if not found
+ */
+function exprmgr_strpos($haystack , $needle ,$offset=0)
+{
+    return mb_strpos($haystack , $needle ,$offset,'UTF-8');
+}
+/**
+ * Finds first occurrence of a unicode string within another
+ * @param string $haystack : checked string
+ * @param string $needle : string to find
+ * @param boolean $before_needle : portion to return
+ * @return string|false 
+ */
+function exprmgr_strstr($haystack,$needle,$before_needle=false)
+{
+    return mb_strstr($haystack,$needle,$before_needle,'UTF-8');
+}
+/**
+ * Make an unicode string lowercase 
+ * @param string $string
+ * @return string
+ */
+function exprmgr_strtolower($string)
+{
+    return mb_strtolower ($string,'UTF-8');
+}
+/**
+ * Make an unicode string uppercase 
+ * @param string $string
+ * @return string
+ */
+function exprmgr_strtoupper($string)
+{
+    return mb_strtoupper ($string,'UTF-8');
+}
+/**
+ * Get part of unicode string
+ * @param string $string
+ * @param int $start
+ * @param int $end
+ * @return string
+ */
+function exprmgr_substr($string,$start,$end=null)
+{
+    return mb_substr($string,$start,$end,'UTF-8');
+}
 /**
  * Sum of values of answered questions which meet the criteria (arg op value)
  * @param <type> $args
diff --git a/scripts/expressions/em_javascript.js b/scripts/expressions/em_javascript.js
index 35d54a666d4..11326b27de5 100644
--- a/scripts/expressions/em_javascript.js
+++ b/scripts/expressions/em_javascript.js
@@ -396,10 +396,15 @@ function LEMstr_replace (search, replace, subject) {
 
 
 
-function LEMstrpos(haystack,needle)
+function LEMstrpos(haystack,needle,offset)
 {
-    var str = new String(haystack);
-    return str.search(needle);
+    var haystack = haystack + '';
+    var needle = needle + '';
+    var index = 0;
+    if ((index = haystack.indexOf(needle, offset)) !== -1) {
+        return index;
+    }
+    return false;
 }
 
 function LEMempty(v)