diff --git a/dlls/jscript/compile.c b/dlls/jscript/compile.c
index 981ae963ca8..2e18c509c0f 100644
--- a/dlls/jscript/compile.c
+++ b/dlls/jscript/compile.c
@@ -75,7 +75,7 @@ static void dump_instr_arg(instr_arg_type_t type, instr_arg_t *arg)
 {
     switch(type) {
     case ARG_STR:
-        TRACE_(jscript_disas)("\t%s", debugstr_w(arg->str));
+        TRACE_(jscript_disas)("\t%s", debugstr_jsstr(arg->str));
         break;
     case ARG_BSTR:
         TRACE_(jscript_disas)("\t%s", debugstr_wn(arg->bstr, SysStringLen(arg->bstr)));
@@ -119,16 +119,37 @@ static inline void *compiler_alloc(bytecode_t *code, size_t size)
     return jsheap_alloc(&code->heap, size);
 }
 
-static WCHAR *compiler_alloc_string(bytecode_t *code, const WCHAR *str)
+static jsstr_t *compiler_alloc_string_len(compiler_ctx_t *ctx, const WCHAR *str, unsigned len)
 {
-    size_t size;
-    WCHAR *ret;
+    jsstr_t *new_str;
 
-    size = (strlenW(str)+1)*sizeof(WCHAR);
-    ret = compiler_alloc(code, size);
-    if(ret)
-        memcpy(ret, str, size);
-    return ret;
+    if(!ctx->code->str_pool_size) {
+        ctx->code->str_pool = heap_alloc(8 * sizeof(jsstr_t*));
+        if(!ctx->code->str_pool)
+            return NULL;
+        ctx->code->str_pool_size = 8;
+    }else if(ctx->code->str_pool_size == ctx->code->str_cnt) {
+        jsstr_t **new_pool;
+
+        new_pool = heap_realloc(ctx->code->str_pool, ctx->code->str_pool_size*2*sizeof(jsstr_t*));
+        if(!new_pool)
+            return NULL;
+
+        ctx->code->str_pool = new_pool;
+        ctx->code->str_pool_size *= 2;
+    }
+
+    new_str = jsstr_alloc_len(str, len);
+    if(!new_str)
+        return NULL;
+
+    ctx->code->str_pool[ctx->code->str_cnt++] = new_str;
+    return new_str;
+}
+
+static jsstr_t *compiler_alloc_string(compiler_ctx_t *ctx, const WCHAR *str)
+{
+    return compiler_alloc_string_len(ctx, str, strlenW(str));
 }
 
 static BOOL ensure_bstr_slot(compiler_ctx_t *ctx)
@@ -216,9 +237,9 @@ static HRESULT push_instr_int(compiler_ctx_t *ctx, jsop_t op, LONG arg)
 static HRESULT push_instr_str(compiler_ctx_t *ctx, jsop_t op, const WCHAR *arg)
 {
     unsigned instr;
-    WCHAR *str;
+    jsstr_t *str;
 
-    str = compiler_alloc_string(ctx->code, arg);
+    str = compiler_alloc_string(ctx, arg);
     if(!str)
         return E_OUTOFMEMORY;
 
@@ -268,9 +289,9 @@ static HRESULT push_instr_bstr_uint(compiler_ctx_t *ctx, jsop_t op, const WCHAR
 static HRESULT push_instr_uint_str(compiler_ctx_t *ctx, jsop_t op, unsigned arg1, const WCHAR *arg2)
 {
     unsigned instr;
-    WCHAR *str;
+    jsstr_t *str;
 
-    str = compiler_alloc_string(ctx->code, arg2);
+    str = compiler_alloc_string(ctx, arg2);
     if(!str)
         return E_OUTOFMEMORY;
 
@@ -711,7 +732,7 @@ static HRESULT compile_typeof_expression(compiler_ctx_t *ctx, unary_expression_t
 
     if(is_memberid_expr(expr->expression->type)) {
         if(expr->expression->type == EXPR_IDENT)
-            return push_instr_str(ctx, OP_typeofident, ((identifier_expression_t*)expr->expression)->identifier);
+            return push_instr_bstr(ctx, OP_typeofident, ((identifier_expression_t*)expr->expression)->identifier);
 
         op = OP_typeofid;
         hres = compile_memberid_expression(ctx, expr->expression, 0);
@@ -738,13 +759,11 @@ static HRESULT compile_literal(compiler_ctx_t *ctx, literal_t *literal)
         return push_instr_str(ctx, OP_str, literal->u.wstr);
     case LT_REGEXP: {
         unsigned instr;
-        WCHAR *str;
+        jsstr_t *str;
 
-        str = compiler_alloc(ctx->code, (literal->u.regexp.str_len+1)*sizeof(WCHAR));
+        str = compiler_alloc_string_len(ctx, literal->u.regexp.str, literal->u.regexp.str_len);
         if(!str)
             return E_OUTOFMEMORY;
-        memcpy(str, literal->u.regexp.str, literal->u.regexp.str_len*sizeof(WCHAR));
-        str[literal->u.regexp.str_len] = 0;
 
         instr = push_instr(ctx, OP_regexp);
         if(!instr)
@@ -1796,10 +1815,13 @@ void release_bytecode(bytecode_t *code)
 
     for(i=0; i < code->bstr_cnt; i++)
         SysFreeString(code->bstr_pool[i]);
+    for(i=0; i < code->str_cnt; i++)
+        jsstr_release(code->str_pool[i]);
 
     heap_free(code->source);
     jsheap_free(&code->heap);
     heap_free(code->bstr_pool);
+    heap_free(code->str_pool);
     heap_free(code->instrs);
     heap_free(code);
 }
diff --git a/dlls/jscript/engine.c b/dlls/jscript/engine.c
index 66e2b92dd4c..44c8333844e 100644
--- a/dlls/jscript/engine.c
+++ b/dlls/jscript/engine.c
@@ -549,7 +549,7 @@ static inline unsigned get_op_int(exec_ctx_t *ctx, int i){
     return ctx->code->instrs[ctx->ip].u.arg[i].lng;
 }
 
-static inline const WCHAR *get_op_str(exec_ctx_t *ctx, int i){
+static inline jsstr_t *get_op_str(exec_ctx_t *ctx, int i){
     return ctx->code->instrs[ctx->ip].u.arg[i].str;
 }
 
@@ -718,11 +718,11 @@ static HRESULT interp_throw_ref(exec_ctx_t *ctx)
 static HRESULT interp_throw_type(exec_ctx_t *ctx)
 {
     const HRESULT hres = get_op_uint(ctx, 0);
-    const WCHAR *str = get_op_str(ctx, 1);
+    jsstr_t *str = get_op_str(ctx, 1);
 
-    TRACE("%08x %s\n", hres, debugstr_w(str));
+    TRACE("%08x %s\n", hres, debugstr_jsstr(str));
 
-    return throw_type_error(ctx->script, hres, str);
+    return throw_type_error(ctx->script, hres, str->str);
 }
 
 /* ECMA-262 3rd Edition    12.14 */
@@ -1134,35 +1134,24 @@ static HRESULT interp_double(exec_ctx_t *ctx)
 /* ECMA-262 3rd Edition    7.8.4 */
 static HRESULT interp_str(exec_ctx_t *ctx)
 {
-    const WCHAR *arg = get_op_str(ctx, 0);
-    jsstr_t *str;
+    jsstr_t *str = get_op_str(ctx, 0);
 
-    TRACE("%s\n", debugstr_w(arg));
+    TRACE("%s\n", debugstr_jsstr(str));
 
-    str = jsstr_alloc(arg);
-    if(!str)
-        return E_OUTOFMEMORY;
-
-    return stack_push(ctx, jsval_string(str));
+    return stack_push(ctx, jsval_string(jsstr_addref(str)));
 }
 
 /* ECMA-262 3rd Edition    7.8 */
 static HRESULT interp_regexp(exec_ctx_t *ctx)
 {
-    const WCHAR *source = get_op_str(ctx, 0);
+    jsstr_t *source = get_op_str(ctx, 0);
     const unsigned flags = get_op_uint(ctx, 1);
     jsdisp_t *regexp;
-    jsstr_t *src;
     HRESULT hres;
 
-    TRACE("%s %x\n", debugstr_w(source), flags);
+    TRACE("%s %x\n", debugstr_jsstr(source), flags);
 
-    src = jsstr_alloc(source);
-    if(!src)
-        return E_OUTOFMEMORY;
-
-    hres = create_regexp(ctx->script, src, flags, &regexp);
-    jsstr_release(src);
+    hres = create_regexp(ctx->script, source, flags, &regexp);
     if(FAILED(hres))
         return hres;
 
diff --git a/dlls/jscript/engine.h b/dlls/jscript/engine.h
index 49232eed75a..9123a2bb8dc 100644
--- a/dlls/jscript/engine.h
+++ b/dlls/jscript/engine.h
@@ -121,7 +121,7 @@ OP_LIST
 typedef union {
     BSTR bstr;
     LONG lng;
-    WCHAR *str;
+    jsstr_t *str;
     unsigned uint;
 } instr_arg_t;
 
@@ -175,6 +175,10 @@ typedef struct _bytecode_t {
     unsigned bstr_pool_size;
     unsigned bstr_cnt;
 
+    jsstr_t **str_pool;
+    unsigned str_pool_size;
+    unsigned str_cnt;
+
     struct _bytecode_t *next;
 } bytecode_t;