www.webdeveloper.com
Results 1 to 9 of 9

Thread: [RESOLVED] Adding to array from for loop

  1. #1
    Join Date
    May 2011
    Posts
    8

    resolved [RESOLVED] Adding to array from for loop

    Hi, When I try to write a value to the array, loop stops.

    Code:
    var colNums = new Array[5];
    
    function multiplicationTable(){
    	// Random Num Cols
    	for (var i=0; i<5; i++){
    		var randomColNum=Math.floor(Math.random()*100)+1;
    		document.getElementById("col_"+i).innerHTML = randomColNum;	
    		colNums[i]=randomColNum; //Trying to write value to array, stops loop
    	}
    Thanks for any help.

  2. #2
    Join Date
    Jun 2004
    Location
    Portsmouth UK
    Posts
    2,709
    Code:
    <!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN"
        "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
    
    <html xmlns="http://www.w3.org/1999/xhtml" xml:lang="en" lang="en">
    
    <head>
      <title></title>
    </head>
    
    <body>
    <script> vic=0; </script>
    <form name=Show id=Show style="position:absolute;visibility:visible;top:700px;left:0px;" >
    <input size=100 name=Show0 >
    <input size=10 name=Show1 >
    <input size=10 name=Show2 >
    <input size=10 name=Show3 >
    <input size=10 name=Show4 >
    <input size=10 name=Show5 >
    <input size=10 name=Show6 >
    <input size=10 name=Show7 >
    <input size=10 name=Show8 >
    <input size=10 name=Show9 ><br>
    <textarea name=TA rows=1 cols=100 ></textarea>
    </form>
    <script   type="text/javascript">
    /*<![CDATA[*/
    var colNums = [];
    
    //function multiplicationTable(){
    	// Random Num Cols
    	for (var i=0; i<5; i++){
    		var randomColNum=Math.floor(Math.random()*100)+1;
    //		document.getElementById("col_"+i).innerHTML = randomColNum;
    		colNums[i]=randomColNum; //Trying to write value to array, stops loop
    	}
    document.Show.Show0.value=colNums;
    /*]]>*/
    </script>
    </body>
    
    </html>
    Vic

    God loves you and will never love you less.

    http://www.vicsjavascripts.org/Home.htm
    If my post has been useful please donate to http://www.operationsmile.org.uk/

  3. #3
    Join Date
    May 2011
    Posts
    8
    Changing:
    Code:
    var colNums = new Array[5];
    To:
    Code:
    var colNums = new Array[5];
    Did the trick.

    Thank you.

  4. #4
    Join Date
    May 2011
    Posts
    8
    I meant to var colNums = [5];
    Can you tell me what I don't need 'new Array'?
    Thank you.

  5. #5
    Join Date
    Jul 2008
    Location
    urbana, il
    Posts
    2,787
    Quote Originally Posted by acbmse View Post
    I meant to var colNums = [5];
    Can you tell me what I don't need 'new Array'?
    Thank you.
    colNums = [5] produces the following array: [5]...
    you over-write the only element first thing in your loop, so you never noticed the 5. javascript expands arrays to their highest numbered index, so adding elements in a loop expands the array each cycle.

    you really just need to say colNums= [];
    Create, Share, and Debug HTML pages and snippets with a cool new web app I helped create: pagedemos.com

  6. #6
    Join Date
    May 2011
    Posts
    8
    Thanks so much. That makes sense.
    I'm just starting to learn JavaScript and this is a big help.
    Just one more question if you don't mind, why don't we use "new Array".

  7. #7
    Join Date
    May 2011
    Posts
    8
    Sorry.
    In my original code I used; var colNums = new Array[5];

    When we change it to; var colNums = []; my script works.

    So, I guess my question is, what is the difference in using 'new Array' in the var and not using it?

    Hope this makes more sense

  8. #8
    Join Date
    Jul 2008
    Location
    urbana, il
    Posts
    2,787
    Quote Originally Posted by acbmse View Post
    So, I guess my question is, what is the difference in using 'new Array' in the var and not using it?

    (new Array) == ([])

    just as

    (new Object) == ({})
    Create, Share, and Debug HTML pages and snippets with a cool new web app I helped create: pagedemos.com

  9. #9
    Join Date
    May 2011
    Posts
    8
    Thanks for your help

Thread Information

Users Browsing this Thread

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

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 0.17672 seconds
  • Memory Usage 2,921KB
  • Queries Executed 15 (?)
More Information
Template Usage (34):
  • (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
  • (2)bbcode_quote
  • (1)footer
  • (1)forumjump
  • (1)forumrules
  • (1)gobutton
  • (1)header
  • (1)headinclude
  • (1)headinclude_bottom
  • (9)memberaction_dropdown
  • (1)navbar
  • (4)navbar_link
  • (1)navbar_moderation
  • (1)navbar_noticebit
  • (1)navbar_tabs
  • (2)option
  • (9)postbit
  • (9)postbit_onlinestatus
  • (9)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 (70):
  • 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_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