diff --git a/dlls/jscript/engine.h b/dlls/jscript/engine.h
index 0cd4c404a8..7dcfc13d5c 100644
--- a/dlls/jscript/engine.h
+++ b/dlls/jscript/engine.h
@@ -43,9 +43,9 @@ typedef struct _func_stack {
 typedef struct _parser_ctx_t {
     LONG ref;
 
-    const WCHAR *ptr;
-    const WCHAR *begin;
+    WCHAR *begin;
     const WCHAR *end;
+    const WCHAR *ptr;
 
     script_ctx_t *script;
     source_elements_t *source;
diff --git a/dlls/jscript/parser.y b/dlls/jscript/parser.y
index 9cae524ed2..0683ab68f3 100644
--- a/dlls/jscript/parser.y
+++ b/dlls/jscript/parser.y
@@ -1594,6 +1594,7 @@ void parser_release(parser_ctx_t *ctx)
     if(--ctx->ref)
         return;
 
+    heap_free(ctx->begin);
     jsheap_free(&ctx->heap);
     heap_free(ctx);
 }
@@ -1615,8 +1616,14 @@ HRESULT script_parse(script_ctx_t *ctx, const WCHAR *code, const WCHAR *delimite
     parser_ctx->hres = JSCRIPT_ERROR|IDS_SYNTAX_ERROR;
     parser_ctx->is_html = delimiter && !strcmpiW(delimiter, html_tagW);
 
-    parser_ctx->begin = parser_ctx->ptr = code;
-    parser_ctx->end = code + strlenW(code);
+    parser_ctx->begin = heap_strdupW(code);
+    if(!parser_ctx->begin) {
+        heap_free(parser_ctx);
+        return E_OUTOFMEMORY;
+    }
+
+    parser_ctx->ptr = parser_ctx->begin;
+    parser_ctx->end = parser_ctx->begin + strlenW(parser_ctx->begin);
 
     script_addref(ctx);
     parser_ctx->script = ctx;