用 JavaScript 搜索代碼中是否加載了黃色部分的 JS如果加載了彈出“JS已加載”否則彈出“未加載”請問我寫的 JS 為什么不能實現(xiàn)該功能？function(){var watermark = document.getElementsByTagName("script");for (var i =0; i<watermark.length; i++)if (watermark[i].src == "http://www-05preview.ibm.com/sk/_dev/mikec/watermark/watermark.js")?? ?{alert ("JS已加載"); }else?? ?{alert ("未加載);?? ?return false;?? ?}}javascript:(function(){var watermark = document.getElementsByTagName("script");for (var i =0; i<watermark.length; i++)if (watermark[i].src =="http://www-05preview.ibm.com/sk/_dev/mikec/watermark/watermark.js"){alert ("JS已加載"); }else{alert ("未加載);return false;})();