diff --git a/cJSON.c b/cJSON.c
index 1b7c085..82eccbb 100644
--- a/cJSON.c
+++ b/cJSON.c
@@ -33,6 +33,7 @@
 
 static int cJSON_strcasecmp(const char *s1,const char *s2)
 {
+	if (!s1) return (s1==s2)?0:1;if (!s2) return 1;
 	for(; tolower(*s1) == tolower(*s2); ++s1, ++s2)	if(*s1 == 0)	return 0;
 	return tolower(*(const unsigned char *)s1) - tolower(*(const unsigned char *)s2);
 }