1、 ||含义 : 返回第一个有效值
eg :
<script type="text/javascript"> var a=""; var c = a || "||返回第一个有效值"; alert(c); </script>
返回 : 后者值
2、window可接受的事件 onload
onload事件会在页面or图像加载完成后立即发生
<html> <head> <script type="text/javascript"> function load() { alert('onload 事件会在页面或图像加载完成后立即发生'); } </script> </head> <body onload="load()"> <div>国庆厦门之旅爽爽的</div> <div>国庆厦门之旅爽爽的</div> <div>国庆厦门之旅爽爽的</div> <div>国庆厦门之旅爽爽的</div> <div>国庆厦门之旅爽爽的</div> <div>国庆厦门之旅爽爽的</div> <div>国庆厦门之旅爽爽的</div> <div>国庆厦门之旅爽爽的</div> <div>国庆厦门之旅爽爽的</div> <div>国庆厦门之旅爽爽的</div> <div>国庆厦门之旅爽爽的</div> <div>国庆厦门之旅爽爽的</div> <div>国庆厦门之旅爽爽的</div> <div>国庆厦门之旅爽爽的</div> <div>国庆厦门之旅爽爽的</div> <div>国庆厦门之旅爽爽的</div> </body> </html>