pub fn array_new_with_length() {
    let arr = js_sys::Array::new_with_length(3);
    arr.set(0,JsValue::from_f64(1.0));    
    arr.set(1,JsValue::from_f64(2.0));    
    arr.set(2,JsValue::from_f64(3.0));                            
    web_sys::console::log(&arr);                        
}