javascript slideshow - can't get the first slide and last slide button to work.

samhor · 01-17-2013, 04:19 AM

Hello All,

I have made the below js slideshow but i can't seem to get the button to take you back to the first/last slide
Any ideas?

Code:

<p><center><h1> Slide Show - Devices</h1></center></p>
	    <script language="JavaScript">
var count = 0
var images = new Array('bblogo.jpg','applelogo.jpg','alogo.jpg','iphone45.jpg')
function imageslideshow( btnselection){

 if ( btnselection == 'next' && count <=2){
 count++
 }

 if ( btnselection == 'back' && count >=1){
 count --;
 }
  if ( btnselection == 'firstslide' && count >=count+1){
 count 
 if ( btnselection == 'lastslide' && count >=count+4){
 count 
 }
 
  document.getElementById("imagecount").innerHTML = (count+1)+" of 4 <br> <img src='images/"+images[count]+"'>"
  
}  
</script>
<div id="imagecount"><script>imageslideshow()</script></div>
<input type="button" value="Previous" onclick="imageslideshow('back')">
<input type="button" value="Next" onclick="imageslideshow('next')">
<input type="button" value="First Slide" onclick="imageslideshow('firstslide')">
<input type="button" value="Last Slide" onclick="imageslideshow('lastslide')">

devnull69 · 01-17-2013, 07:12 AM

Oh my ... there are several issues in your code

1 - language="Javascript" should be replaced by type="text/javascript"
2 - You should get used to correct indentation of code and related brackets

Code:

var count = 0
var images = new Array('bblogo.jpg','applelogo.jpg','alogo.jpg','iphone45.jpg')

function imageslideshow( btnselection){

 if ( btnselection == 'next' && count <=2){
   count++
 }

 if ( btnselection == 'back' && count >=1){
   count --;
 }
 
 if ( btnselection == 'firstslide' && count >=count+1){
   count 
 
 if ( btnselection == 'lastslide' && count >=count+4){
   count 
 }
 
 document.getElementById("imagecount").innerHTML = (count+1)+" of 4 <br> <img src='images/"+images[count]+"'>"
  
}

Then you can immediately see that you are missing a closing } for one of the if statements

3 - In two of the if statements you just have "count" ... what do you want to do for those if's? You want to SET a certain value for count, no matter what the current value is

Code:

 if ( btnselection == 'firstslide'){
   count=0;
 }
 if ( btnselection == 'lastslide'){
   count=3;
 }

samhor · 01-17-2013, 11:56 AM

Quote:

Originally Posted by devnull69

Oh my ... there are several issues in your code

1 - language="Javascript" should be replaced by type="text/javascript"
2 - You should get used to correct indentation of code and related brackets

Code:

var count = 0
var images = new Array('bblogo.jpg','applelogo.jpg','alogo.jpg','iphone45.jpg')

function imageslideshow( btnselection){

 if ( btnselection == 'next' && count <=2){
   count++
 }

 if ( btnselection == 'back' && count >=1){
   count --;
 }
 
 if ( btnselection == 'firstslide' && count >=count+1){
   count 
 
 if ( btnselection == 'lastslide' && count >=count+4){
   count 
 }
 
 document.getElementById("imagecount").innerHTML = (count+1)+" of 4 <br> <img src='images/"+images[count]+"'>"
  
}

Then you can immediately see that you are missing a closing } for one of the if statements

3 - In two of the if statements you just have "count" ... what do you want to do for those if's? You want to SET a certain value for count, no matter what the current value is

Code:

 if ( btnselection == 'firstslide'){
   count=0;
 }
 if ( btnselection == 'lastslide'){
   count=3;
 }

Hi

In regards to 3 -

Code:

 if ( btnselection == 'firstslide' && count >=count+1){
   count 
 
 if ( btnselection == 'lastslide' && count >=count+4){
   count 
 }

I wanted the above to take me to first and last slide as marked in bold. I thought by putting in count shown in red would take the count and take me to the first and last slide respectedly. How would i do it?

devnull69 · 01-18-2013, 08:46 AM

You'd do it exactly as I mentioned before

Code:

 if ( btnselection == 'firstslide'){
   count=0;
 }
 if ( btnselection == 'lastslide'){
   count=3;
 }

The condition to take you to the first/last slide is ONLY the clicked button and not the current value of "count". In order to take you to the first slide, set the count to 0. In order to take you to the last slide, set the count to 3