Javascript simple performance issues and study notes

< Script type="text/javascript" SRC ="file1.js" defer />  

, test the defer attribute example:

<script defer>alert("defer");</script>  
<script>alert("script");</script>  
<script>  
window.onload = function() {  
alert("load");  
};  
</script>

Time is limited, so let's do that today