Lets apply the Best practices to the Image Gallery .

/***　　　　　　index.html　　　　　　***/

    
              
          
Snapshiots
    
      
        
       
             Fireworks         
        
       
             Coffee         
        
       
             Rose         
        
       
             Big Ben         
    
      
    
      
        
           
      
    
      
        
       
Choose an image
    
      
        

/***　　　　　　showPic.js　　　　　　***/

/** * Created by Administrator on 9/9/2015. */function addLoadEvent(func) {    var oldonload = window.onload;    if( typeof window.onload != 'function') {        window.onload = func;    } else {        window.onload = function() {            oldonload();            func();        }    }}function prepareGallery() {    if( !document.getElementsByTagName )  return false;    if( !document.getElementById ) return false;    if( !document.getElementById("imagegallery") ) return false;    var gallery = document.getElementById("imagegallery");    var links = gallery.getElementsByTagName("a");    for(var i=0; i

/***　　　　　　layout.css　　　　　　***/

body{
        font-family: "Helvetica", "Arial", serif;    color: #333;    background-color: #ccc;    margin: 1em 10%;}h1{
        color: #333;    /*background-color: #777;*/}a{
        color: #c60;    background-color: transparent;    font-weight: bold;    text-decoration: none;}ul{
        padding: 0;}li{
        float: left;    padding: 1em;    list-style: none;}img {
        display: block;    clear: both;}

 

I think there is a function you can use in the furture, thats the addLoadEvent() :

function addLoadEvent(func) {    var oldonload = window.onload;    if( typeof window.onload != 'function') {        window.onload = func;    } else {        window.onload = function() {            oldonload();            func();        }    }}

This is a good plan for the future expansion. 

This effectively creates a queue of functions to be executed when the page loads.

To add functions to this queue, I just need to write :

        addLoadEvent( firstFunction );

        addLoadEvent( secondFunction );