www.webdeveloper.com
Results 1 to 3 of 3

Thread: Newbie! Simple javscript code not working.

Hybrid View

  1. #1
    Join Date
    Jul 2013
    Posts
    1

    Newbie! Simple javscript code not working.

    I'm new to javascript. My code (in the head section) below is not working for some reason. I know the problem is in the line " if (lfckv == 'true') " . It says "NOT ticked" when I check or uncheck the checkbox.

    Code:
     <script>
                function exefunction(){
                    var lfckv = document.getElementById("lifecheck").checked;
                    if (lfckv == 'true')
    				{
    				alert("ticked");
    				}
    				else
    				{
    				alert("NOT ticked");
    			}
    			}
    				</script>
    My HTML code:

    HTML Code:
    <input type="checkbox" name="tag" value="tag"  id="lifecheck"  onclick="exefunction()"/> Tag this message

  2. #2
    Join Date
    Jun 2008
    Posts
    106
    You have 2 problems.
    1) You are trying to compare a boolean to a string when you should be comparing a boolean to another boolean.

    2) You're using the double equals operator (==), not the triple equals operator (===).
    The triple equals operator is better in 99% of cases. It does not do type coercion (Google it); it checks if the values are identical.

    Here are some examples to show why you shouldn't use == (aka, the eqeq operator).
    Code:
    true == 'true'     // false
    false == 'false'   // false
    false == 0       // true
    true == '1'        // true
    true == 1         // true
    null == undefined     // true




    So we simply change your if () statement in your code to compare .checked to a boolean and not a string, and we also use ===.
    Code:
    function exefunction() {
        var lfckv = document.getElementById("lifecheck").checked;
        if (lfckv === true) {
            alert('ticked');
        } else {
            alert('NOT ticked');
        }
    }
    Or, since you always call alert (just with a different string), you could shorten your function to this:
    Code:
    function exefunction() {
        alert((document.getElementById("lifecheck").checked === true ? 'NOT ' : '') + 'ticked');
    }
    That is using the ternary operator to shorten it to one line. No variables are necessary because we didn't use anything more than once.
    Last edited by tenfold; 07-31-2013 at 09:50 AM.

  3. #3
    Join Date
    Oct 2010
    Location
    Versailles, France
    Posts
    1,290
    Or , simply ?

    if (lfckv) alert('ticked'); else alert('NOT ticked');

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 0.13024 seconds
  • Memory Usage 2,932KB
  • Queries Executed 13 (?)
More Information
Template Usage (31):
  • (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
  • (4)bbcode_code
  • (1)bbcode_html
  • (1)footer
  • (1)forumjump
  • (1)forumrules
  • (1)gobutton
  • (1)header
  • (1)headinclude
  • (1)headinclude_bottom
  • (3)memberaction_dropdown
  • (1)navbar
  • (4)navbar_link
  • (1)navbar_moderation
  • (1)navbar_noticebit
  • (1)navbar_tabs
  • (2)option
  • (3)postbit
  • (3)postbit_onlinestatus
  • (3)postbit_wrapper
  • (1)showthread_list
  • (1)spacer_close
  • (1)spacer_open
  • (1)tagbit_wrapper 

Phrase Groups Available (6):
  • global
  • inlinemod
  • postbit
  • posting
  • reputationlevel
  • showthread
Included Files (27):
  • ./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
  • ./includes/functions_threadedmode.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 (72):
  • 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_threaded
  • showthread_threaded_construct_link
  • 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