/*
 * Program - JavaScript Image Slider
 * File Name - script.js
 * Author - Shovon
 * Web site - http://www.shuvorim.tk
 * Email - ahsanul_haque_shovon@yahoo.com
 * (C) http://www.shuvorim.tk
 * All rights reserved.
 */

//declaring necessary local variables
var img = new Array(11);  //array to hold the images
var start = null;  //start pointer
var counter = 1;  //counts the image sequences
var delayTime = null;  //user defined delay time of the slide show
var tempo = 4;  //temporary variable for holding the delay

if(document.images) //pre-load all the images before starting the show
{
  //Change the looping condition if you want to add or remove images. 
  //Do not load too many images, it will slow down the page loading 
  //time [e.g. 20 or above images]. Please use appropriate image 
  //extensions, if you aren't using ".gif" images.

  for(i = 1; i < 11; i++)
  {
    img[i] = new Image();
    img[i].src = "./images/" + i + ".gif";
  }
}

//function for getting the user defined delay time
function getDelayTime(dlTime)
{
  var temp = parseInt(dlTime);  //parsing the delay time string to integer

  if(temp != NaN)  //if the temp variable is not equal to a NaN
  {
    delayTime = temp * 1000;  //then multiply temp by 1000 miliseconds
  }

  else
  {
    delayTime = 4000;  //using the default delay time - 4 seconds
  }
}

//function for changing the images
//this function is used for auto slide show
function anim()
{
  try
  {
    if(counter < 11)
    {
      document.initPic.src = img[counter++].src;  //setting the next image
    }

    else
    {
      clearInterval(start);  //clearing the interval

      with(document.form1)
      {
	stShow.disabled = false;  //enabling the 'Start' button
	btnBack.disabled = false;  //enabling the 'Back' button
	btnNext.disabled = false;  //enabling the 'Next' button
	spShow.disabled = true;  //disabling the 'Stop' button
      }
    }
  }

  catch(exception)
  {
    //catch the error and do nothing!
  }
}

//function for starting the slide show
//'Start' button calls it whenever clicked

function slide()
{
  getDelayTime(document.form1.delay.value);  //getting user defined delay time

  with(document.form1)
  {
    start = setInterval("anim()", delayTime);  //setting the page interval
    stShow.disabled = true;  //disabling the 'Start' button
    btnBack.disabled = true;  //disabling the 'Back' button
    btnNext.disabled = true;  //disabling the 'Next' button
    spShow.disabled = false;  //enabling the 'Stop' button
  }
}

//function for the 'Back' button
function back()
{
  try
  {
    if(counter > 1)
    {
      document.initPic.src = img[--counter].src;
    }
  }

  catch(exception)
  {
    //catch the error and do nothing!
  }
}

//function for the 'Next' button
function next()
{
  try
  {
    if(counter < 11)
    {
      document.initPic.src = img[++counter].src;
    }
  }

  catch(exception)
  {
    //catch the error and do nothing!
  }
}

//function to stop the slide show
function stopSlide()
{
  clearInterval(start);  //clearing the interval

  with(document.form1)
  {
    stShow.disabled = false;  //enabling the 'Start' button
    btnBack.disabled = false;  //enabling the 'Back' button
    btnNext.disabled = false;  //enabling the 'Next' button
    spShow.disabled = true;  //disabling the 'Stop' button
  }
}

//function for increasing the delay time
function incDelay()
{
  tempo++;  //increasing the value of the temporary variable

  if(tempo >= 30)  //not more than to 30 seconds
  {
    tempo = 30;  //set tempo 30 again
  }

  document.form1.delay.value = tempo;
}

//function for decreasing the delay time
function decDelay()
{
  tempo--;  //decreasing the value of the temporary variable

  if(tempo <= 1)  //not less than to 1 second
  {
    tempo = 1;  //set tempo 1 again
  }

  document.form1.delay.value = tempo;
}