www.webdeveloper.com
Results 1 to 6 of 6

Thread: CSS Background Image using a variable

  1. #1
    Join Date
    Jul 2010
    Posts
    3

    CSS Background Image using a variable

    Hi All,

    I am attempting to put a simple slideshow of pictures on our company's website as the background of a div. The code I have works fine for a single picture:

    obj.style.backgroundImage = 'url("photo.jpg")';

    but does not work when I try to use a variable for the file name instead of the file name itself, ie:

    obj.style.backgroundImage = 'url("processed[i].src")';

    Is there anyway to set the background image using variable names? I really don't want to have to use a switch statement with each case being a different picture. Any ideas?

    Thanks!

    Brian Rost

  2. #2
    Join Date
    Mar 2010
    Posts
    2,803
    In its simplest form maybe do the following:

    1) preload the slideshow images using javascript in the <head>

    2) create a window.onload function that uses setInterval() to then cycle through the images at whatever time period you want.

    Back 3-4 months ago I posted some example code in reply to a similar query.

  3. #3
    Join Date
    Jul 2010
    Posts
    3
    I have this code, and am just wondering about that one line that doesn't work the way I want it to. I'm not exactly sure what you're suggesting, could you elaborate? My javascript knowledge is limited, thanks

    <script language="JavaScript1.2">
    var HomeSlideArray=new Array()
    HomeSlideArray[0]="Images/photo1.jpg"
    HomeSlideArray[1]="Images/photo2.jpg"
    HomeSlideArray[2]="Images/photo3.jpg"
    HomeSlideArray[3]="Images/photo4.jpg"
    HomeSlideArray[4]="Images/photo5.jpg"
    HomeSlideArray[5]="Images/photo6.jpg"
    HomeSlideArray[6]="Images/photo7.jpg"
    HomeSlideArray[7]="Images/photo8.jpg"
    var speed=1
    var processed=new Array()
    for (i=0;i<HomeSlideArray.length;i++){
    processed[i]=new Image()
    processed[i].src=HomeSlideArray[i]
    }
    var inc=-1
    function slideback(){
    if (inc<HomeSlideArray.length-1)
    inc++
    else
    inc=0
    var obj = document.getElementById('main_image');
    obj.style.backgroundImage = 'url("processed[inc].src")';
    }
    if (document.all||document.getElementById)
    window.onload=new Function('setInterval("slideback()",speed)')
    </script>

  4. #4
    Join Date
    Mar 2010
    Posts
    2,803
    try

    Code:
     
    obj.style.backgroundImage = 'url("'+processed[inc].src+'")';
    so that processed[inc].src is actually evaluated and not taken as part of the string.
    Last edited by tirna; 07-08-2010 at 07:39 PM.

  5. #5
    Join Date
    Aug 2007
    Posts
    3,767
    Code:
    'url("'+processed[inc].src+'")'
    Some general suggestions.
    Code:
    <script type="text/javscript">
    var HomeSlideArray=["photo1.jpg","photo2.jpg","photo3.jpg","photo4.jpg","photo5.jpg","photo6.jpg","photo7.jpg","photo8.jpg"];
    var speed=1; // Every millisecond? Sure you don't mean 1000?
    var processed=[];
    for (i=0;i<HomeSlideArray.length;i++){
    processed[i]=new Image();
    processed[i].src="Images/"+HomeSlideArray[i];
    }
    var inc=-1
    function slideback(){
    if (inc<HomeSlideArray.length-1) {
        inc++;
    }
    else {
    inc=0;
    }
    document.getElementById('main_image').style.backgroundImage = 'url("'+processed[inc].src+'")';
    }
    window.onload=function() {setInterval(slideback,speed);};
    </script>
    If the picture names are that regular, it's even easier.
    Code:
    <script type="text/javscript">
    var no = 8
    var speed=1; // Every millisecond? Sure you don't mean 1000?
    var processed=[];
    for (i=0;i<no;i++){
    processed[i]=new Image();
    processed[i].src="Images/photo"+i+".jpg";
    }
    var inc=-1
    function slideback(){
    if (inc<no-1) {
        inc++;
    }
    else {
    inc=0;
    }
    document.getElementById('main_image').style.backgroundImage = 'url("'+processed[inc].src+'")';
    }
    window.onload=function() {setInterval(slideback,speed);};
    </script>
    Last edited by Declan1991; 07-08-2010 at 07:26 PM.

  6. #6
    Join Date
    Jul 2010
    Posts
    3
    Thanks! That worked perfectly. Thanks for the general code suggestions too, as I said my javascript knowledge isn't the best so the help is much appreciated

Thread Information

Users Browsing this Thread

There are currently 1 users browsing this thread. (0 members and 1 guests)

Tags for this Thread

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •  
HTML5 Development Center

"

"

X vBulletin 4.2.2 Debug Information

  • Page Generation 0.10562 seconds
  • Memory Usage 2,886KB
  • Queries Executed 13 (?)
More Information
Template Usage (33):
  • (1)SHOWTHREAD
  • (1)ad_footer_end
  • (1)ad_footer_start
  • (1)ad_global_above_footer
  • (1)ad_global_below_navbar
  • (1)ad_global_header1
  • (1)ad_global_header2
  • (1)ad_navbar_below
  • (1)ad_showthread_firstpost_sig
  • (1)ad_showthread_firstpost_start
  • (1)ad_thread_first_post_content
  • (1)ad_thread_last_post_content
  • (4)bbcode_code
  • (1)footer
  • (1)forumjump
  • (1)forumrules
  • (1)gobutton
  • (1)header
  • (1)headinclude
  • (1)headinclude_bottom
  • (6)memberaction_dropdown
  • (1)navbar
  • (4)navbar_link
  • (1)navbar_moderation
  • (1)navbar_noticebit
  • (1)navbar_tabs
  • (2)option
  • (6)postbit
  • (6)postbit_onlinestatus
  • (6)postbit_wrapper
  • (1)spacer_close
  • (1)spacer_open
  • (1)tagbit_wrapper 

Phrase Groups Available (6):
  • global
  • inlinemod
  • postbit
  • posting
  • reputationlevel
  • showthread
Included Files (26):
  • ./showthread.php
  • ./global.php
  • ./includes/class_bootstrap.php
  • ./includes/init.php
  • ./includes/class_core.php
  • ./includes/config.php
  • ./includes/functions.php
  • ./includes/functions_navigation.php
  • ./includes/class_friendly_url.php
  • ./includes/class_hook.php
  • ./includes/class_bootstrap_framework.php
  • ./vb/vb.php
  • ./vb/phrase.php
  • ./includes/functions_facebook.php
  • ./includes/functions_calendar.php
  • ./includes/functions_bigthree.php
  • ./includes/class_postbit.php
  • ./includes/class_bbcode.php
  • ./includes/functions_reputation.php
  • ./includes/functions_notice.php
  • ./packages/vbattach/attach.php
  • ./vb/types.php
  • ./vb/cache.php
  • ./vb/cache/db.php
  • ./vb/cache/observer/db.php
  • ./vb/cache/observer.php 

Hooks Called (71):
  • init_startup
  • friendlyurl_resolve_class
  • init_startup_session_setup_start
  • database_pre_fetch_array
  • database_post_fetch_array
  • init_startup_session_setup_complete
  • global_bootstrap_init_start
  • global_bootstrap_init_complete
  • cache_permissions
  • fetch_threadinfo_query
  • fetch_threadinfo
  • fetch_foruminfo
  • load_show_variables
  • load_forum_show_variables
  • global_state_check
  • global_bootstrap_complete
  • global_start
  • style_fetch
  • global_setup_complete
  • showthread_start
  • showthread_getinfo
  • strip_bbcode
  • friendlyurl_clean_fragment
  • friendlyurl_geturl
  • forumjump
  • cache_templates
  • cache_templates_process
  • template_register_var
  • template_render_output
  • fetch_template_start
  • fetch_template_complete
  • parse_templates
  • fetch_musername
  • notices_check_start
  • notices_noticebit
  • process_templates_complete
  • friendlyurl_redirect_canonical
  • showthread_post_start
  • showthread_query_postids
  • showthread_query
  • bbcode_fetch_tags
  • bbcode_create
  • showthread_postbit_create
  • postbit_factory
  • postbit_display_start
  • postbit_imicons
  • bbcode_parse_start
  • bbcode_parse_complete_precache
  • bbcode_parse_complete
  • postbit_display_complete
  • memberaction_dropdown
  • tag_fetchbit
  • tag_fetchbit_complete
  • forumrules
  • navbits
  • navbits_complete
  • build_navigation_data
  • build_navigation_array
  • check_navigation_permission
  • process_navigation_links_start
  • process_navigation_links_complete
  • set_navigation_menu_element
  • build_navigation_menudata
  • build_navigation_listdata
  • build_navigation_list
  • set_navigation_tab_main
  • set_navigation_tab_fallback
  • navigation_tab_complete
  • fb_like_button
  • showthread_complete
  • page_templates