diff --git a/dlls/jscript/jsutils.c b/dlls/jscript/jsutils.c
index 304980d77a..9e49cc7b8a 100644
--- a/dlls/jscript/jsutils.c
+++ b/dlls/jscript/jsutils.c
@@ -449,10 +449,14 @@ HRESULT to_integer(script_ctx_t *ctx, VARIANT *v, jsexcept_t *ei, VARIANT *ret)
     if(FAILED(hres))
         return hres;
 
-    if(V_VT(&num) == VT_I4)
+    if(V_VT(&num) == VT_I4) {
         *ret = num;
-    else
+    }else if(isnan(V_R8(&num))) {
+        V_VT(ret) = VT_I4;
+        V_I4(ret) = 0;
+    }else {
         num_set_val(ret, V_R8(&num) >= 0.0 ? floor(V_R8(&num)) : -floor(-V_R8(&num)));
+    }
 
     return S_OK;
 }
diff --git a/dlls/jscript/tests/api.js b/dlls/jscript/tests/api.js
index 42a79e8f71..80bdf88b98 100644
--- a/dlls/jscript/tests/api.js
+++ b/dlls/jscript/tests/api.js
@@ -231,6 +231,8 @@ tmp = "abc".charAt(-1);
 ok(tmp === "", "'abc',charAt(-1) = " + tmp);
 tmp = "abc".charAt(0,2);
 ok(tmp === "a", "'abc',charAt(0.2) = " + tmp);
+tmp = "abc".charAt(NaN);
+ok(tmp === "a", "'abc',charAt(NaN) = " + tmp);
 
 tmp = "abc".charCodeAt(0);
 ok(tmp === 0x61, "'abc'.charCodeAt(0) = " + tmp);