diff --git a/base/src/nsString.cpp b/base/src/nsString.cpp
index a4c6b86e46a3..8e45375800ac 100644
--- a/base/src/nsString.cpp
+++ b/base/src/nsString.cpp
@@ -965,6 +965,47 @@ PRInt32 nsString::Insert(nsString& aCopy,PRInt32 anOffset,PRInt32 aCount) {
   return aCount;
 }
 
+
+/**
+ * Insert a single unicode char into this string at
+ * a specified offset.
+ *
+ * @update	gess4/22/98
+ * @param   aChar char to be inserted into this string
+ * @param   anOffset is insert pos in str 
+ * @return  the number of chars inserted into this string
+ */
+PRInt32 nsString::Insert(PRUnichar aChar,PRInt32 anOffset){
+
+  //1st optimization: If you're inserting at end, then simply append!
+  if(anOffset<mLength){
+
+    if(mLength+1> mCapacity) {
+      EnsureCapacityFor(mLength+1);
+    }
+
+    PRUnichar* last = mStr + mLength;
+    PRUnichar* first = mStr + anOffset-1;
+    PRUnichar* next = mStr + mLength + 1;
+
+    //Copy rightmost chars, up to offset+aCount...
+    while(first<last) {
+      char ch1=char(*last);
+      char ch2=char(*next);
+      *next=*last;  
+      next--;
+      last--;
+    }
+
+    //now insert new chars, starting at offset
+    mStr[anOffset]=aChar;
+    mLength+=1;
+  }
+  else Append(aChar);
+
+  return 1;
+}
+
 /**-------------------------------------------------------
  *  This method is used to cut characters in this string
  *  starting at anOffset, continuing for aCount chars.
diff --git a/base/src/nsString.h b/base/src/nsString.h
index d02e353530ab..03501ed6fa9a 100644
--- a/base/src/nsString.h
+++ b/base/src/nsString.h
@@ -121,6 +121,7 @@ class NS_BASE nsString {
             PRInt32       Mid(nsString& aCopy,PRInt32 anOffset,PRInt32 aCount);
             PRInt32       Right(nsString& aCopy,PRInt32 aCount);
             PRInt32       Insert(nsString& aCopy,PRInt32 anOffset,PRInt32 aCount=-1);
+            PRInt32       Insert(PRUnichar aChar,PRInt32 anOffset);
 
             nsString&     Cut(PRInt32 anOffset,PRInt32 aCount);
             nsString&     StripChars(const char* aSet);
diff --git a/string/obsolete/nsString.cpp b/string/obsolete/nsString.cpp
index a4c6b86e46a3..8e45375800ac 100644
--- a/string/obsolete/nsString.cpp
+++ b/string/obsolete/nsString.cpp
@@ -965,6 +965,47 @@ PRInt32 nsString::Insert(nsString& aCopy,PRInt32 anOffset,PRInt32 aCount) {
   return aCount;
 }
 
+
+/**
+ * Insert a single unicode char into this string at
+ * a specified offset.
+ *
+ * @update	gess4/22/98
+ * @param   aChar char to be inserted into this string
+ * @param   anOffset is insert pos in str 
+ * @return  the number of chars inserted into this string
+ */
+PRInt32 nsString::Insert(PRUnichar aChar,PRInt32 anOffset){
+
+  //1st optimization: If you're inserting at end, then simply append!
+  if(anOffset<mLength){
+
+    if(mLength+1> mCapacity) {
+      EnsureCapacityFor(mLength+1);
+    }
+
+    PRUnichar* last = mStr + mLength;
+    PRUnichar* first = mStr + anOffset-1;
+    PRUnichar* next = mStr + mLength + 1;
+
+    //Copy rightmost chars, up to offset+aCount...
+    while(first<last) {
+      char ch1=char(*last);
+      char ch2=char(*next);
+      *next=*last;  
+      next--;
+      last--;
+    }
+
+    //now insert new chars, starting at offset
+    mStr[anOffset]=aChar;
+    mLength+=1;
+  }
+  else Append(aChar);
+
+  return 1;
+}
+
 /**-------------------------------------------------------
  *  This method is used to cut characters in this string
  *  starting at anOffset, continuing for aCount chars.
diff --git a/string/obsolete/nsString.h b/string/obsolete/nsString.h
index d02e353530ab..03501ed6fa9a 100644
--- a/string/obsolete/nsString.h
+++ b/string/obsolete/nsString.h
@@ -121,6 +121,7 @@ class NS_BASE nsString {
             PRInt32       Mid(nsString& aCopy,PRInt32 anOffset,PRInt32 aCount);
             PRInt32       Right(nsString& aCopy,PRInt32 aCount);
             PRInt32       Insert(nsString& aCopy,PRInt32 anOffset,PRInt32 aCount=-1);
+            PRInt32       Insert(PRUnichar aChar,PRInt32 anOffset);
 
             nsString&     Cut(PRInt32 anOffset,PRInt32 aCount);
             nsString&     StripChars(const char* aSet);
diff --git a/xpcom/ds/nsString.cpp b/xpcom/ds/nsString.cpp
index a4c6b86e46a3..8e45375800ac 100644
--- a/xpcom/ds/nsString.cpp
+++ b/xpcom/ds/nsString.cpp
@@ -965,6 +965,47 @@ PRInt32 nsString::Insert(nsString& aCopy,PRInt32 anOffset,PRInt32 aCount) {
   return aCount;
 }
 
+
+/**
+ * Insert a single unicode char into this string at
+ * a specified offset.
+ *
+ * @update	gess4/22/98
+ * @param   aChar char to be inserted into this string
+ * @param   anOffset is insert pos in str 
+ * @return  the number of chars inserted into this string
+ */
+PRInt32 nsString::Insert(PRUnichar aChar,PRInt32 anOffset){
+
+  //1st optimization: If you're inserting at end, then simply append!
+  if(anOffset<mLength){
+
+    if(mLength+1> mCapacity) {
+      EnsureCapacityFor(mLength+1);
+    }
+
+    PRUnichar* last = mStr + mLength;
+    PRUnichar* first = mStr + anOffset-1;
+    PRUnichar* next = mStr + mLength + 1;
+
+    //Copy rightmost chars, up to offset+aCount...
+    while(first<last) {
+      char ch1=char(*last);
+      char ch2=char(*next);
+      *next=*last;  
+      next--;
+      last--;
+    }
+
+    //now insert new chars, starting at offset
+    mStr[anOffset]=aChar;
+    mLength+=1;
+  }
+  else Append(aChar);
+
+  return 1;
+}
+
 /**-------------------------------------------------------
  *  This method is used to cut characters in this string
  *  starting at anOffset, continuing for aCount chars.
diff --git a/xpcom/ds/nsString.h b/xpcom/ds/nsString.h
index d02e353530ab..03501ed6fa9a 100644
--- a/xpcom/ds/nsString.h
+++ b/xpcom/ds/nsString.h
@@ -121,6 +121,7 @@ class NS_BASE nsString {
             PRInt32       Mid(nsString& aCopy,PRInt32 anOffset,PRInt32 aCount);
             PRInt32       Right(nsString& aCopy,PRInt32 aCount);
             PRInt32       Insert(nsString& aCopy,PRInt32 anOffset,PRInt32 aCount=-1);
+            PRInt32       Insert(PRUnichar aChar,PRInt32 anOffset);
 
             nsString&     Cut(PRInt32 anOffset,PRInt32 aCount);
             nsString&     StripChars(const char* aSet);
diff --git a/xpcom/string/obsolete/nsString.cpp b/xpcom/string/obsolete/nsString.cpp
index a4c6b86e46a3..8e45375800ac 100644
--- a/xpcom/string/obsolete/nsString.cpp
+++ b/xpcom/string/obsolete/nsString.cpp
@@ -965,6 +965,47 @@ PRInt32 nsString::Insert(nsString& aCopy,PRInt32 anOffset,PRInt32 aCount) {
   return aCount;
 }
 
+
+/**
+ * Insert a single unicode char into this string at
+ * a specified offset.
+ *
+ * @update	gess4/22/98
+ * @param   aChar char to be inserted into this string
+ * @param   anOffset is insert pos in str 
+ * @return  the number of chars inserted into this string
+ */
+PRInt32 nsString::Insert(PRUnichar aChar,PRInt32 anOffset){
+
+  //1st optimization: If you're inserting at end, then simply append!
+  if(anOffset<mLength){
+
+    if(mLength+1> mCapacity) {
+      EnsureCapacityFor(mLength+1);
+    }
+
+    PRUnichar* last = mStr + mLength;
+    PRUnichar* first = mStr + anOffset-1;
+    PRUnichar* next = mStr + mLength + 1;
+
+    //Copy rightmost chars, up to offset+aCount...
+    while(first<last) {
+      char ch1=char(*last);
+      char ch2=char(*next);
+      *next=*last;  
+      next--;
+      last--;
+    }
+
+    //now insert new chars, starting at offset
+    mStr[anOffset]=aChar;
+    mLength+=1;
+  }
+  else Append(aChar);
+
+  return 1;
+}
+
 /**-------------------------------------------------------
  *  This method is used to cut characters in this string
  *  starting at anOffset, continuing for aCount chars.
diff --git a/xpcom/string/obsolete/nsString.h b/xpcom/string/obsolete/nsString.h
index d02e353530ab..03501ed6fa9a 100644
--- a/xpcom/string/obsolete/nsString.h
+++ b/xpcom/string/obsolete/nsString.h
@@ -121,6 +121,7 @@ class NS_BASE nsString {
             PRInt32       Mid(nsString& aCopy,PRInt32 anOffset,PRInt32 aCount);
             PRInt32       Right(nsString& aCopy,PRInt32 aCount);
             PRInt32       Insert(nsString& aCopy,PRInt32 anOffset,PRInt32 aCount=-1);
+            PRInt32       Insert(PRUnichar aChar,PRInt32 anOffset);
 
             nsString&     Cut(PRInt32 anOffset,PRInt32 aCount);
             nsString&     StripChars(const char* aSet);