www.webdeveloper.com
Results 1 to 5 of 5

Thread: calculation result display

  1. #1
    Join Date
    May 2010
    Posts
    2

    calculation result display

    Hi,
    I am a beginner to coding javascript. I have spent many hours trying to get this calculation result to display in the form box in the browser window. I think the calculation is correct because it works when I use a calculator but it doesn't do anything as it is now coded. Do I use parseInt, or Math.round and do I display it by saying return payment;

    Any help would be greatly appreciated! Here's the code by cut and paste method:

    <html>
    <head>
    <title>Final exam 2</TITLE>
    <script>
    /* car payment calculation function coding here */
    <!--
    function calc(myform) {
    var interest = myform.rate.value / 100;
    var total = ((myform.price.value - myform.down.value) * (1 + myform.rate.value));
    var payment = myform.total.value / 60;{
    return payment;
    }

    </script>
    </head>
    <body bgcolor="#FFE4E1">
    <h1>Final Exam Car Payment Calculator(CPC)</h1>
    <p>
    </p><form name="myform" id="myform"><!--are the name and id required? I've seen examples of forms that are referenced in the script. The function is calling "myform" right?-->
    <table border="1">
    <tr>
    <td>Car Price:</td>
    <td><input type="text" value="0" name="price" /></td>

    </tr>
    <tr>
    <td>Interest rate:</td>
    <td><input type="text" value="5.5" name="rate" /></td>
    </tr>
    <tr>
    <td>Number of Years:</td>
    <td>5 years (60 months)
    </td>
    </tr>
    <tr>
    <td>Down Payment:</td>
    <td><input type="text" value="0" name="down" /></td>
    </tr>

    <tr>
    <td>Monthly Payment:</td>
    <td><input type="text" name="payment" onFocus="this.blur();" /></td><!--Why is this blur?-->
    </tr>
    </table>
    <p></p>
    <p>
    <input type="button" value="Calculate" onClick="return calc(this)" />
    <input type="reset" value="Reset" />
    </p></form>

    <hr />
    <h3>Question #2</h3>
    Write a JavaScript function - calc() with parameter/argument to calculate a car payment:
    <ul><li>interest = rate / 100</li>

    <li>total = ((price - down) * (1 + interest))</li>
    <li>payment = total / 60 </li>
    </ul>

    </body>
    </html>

    Thanks, in advance!!

  2. #2
    Join Date
    Mar 2010
    Posts
    2,803
    You have at least 1 syntax error and at least 1 logic error.

    The Firefox error console tells you exactly what the errors are.

    Using some basic Debugging 101 as described here http://www.webdeveloper.com/forum/sh...47#post1074647 you should be able to debug your code using either a debugger or alert() statements to check values of variables and your code logic.

  3. #3
    Join Date
    Oct 2006
    Posts
    939
    The math doesn't look right to me?

    HTML Code:
    <!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN"
    	"http://www.w3.org/TR/html4/strict.dtd">
    <HTML>
    <HEAD><TITLE>Mo8-40am49</TITLE>
    <META http-equiv=Content-Type content="text/html; charset=UTF-8">
    <STYLE type=text/CSS>
    
    
    </STYLE>
    <SCRIPT type="text/javascript">
    function calc(myform) {
    	var f=document.forms[0].elements;				// identify forms and inputs by their index rather than name or id (personal prefrence)
    	var interest = f[1].value / 100; 				// alert(interest)
    	var total = ((f[0].value - f[2].value) * (1 + f[1].value)); 	// alert(total)
    	 f[3].value=(total / 60).toFixed(2);				// monthly payment
    	f[4].value=total
    }
    
    </SCRIPT>
    <META content="MSHTML 6.00.2900.2963" name=GENERATOR></HEAD>
    <BODY scroll="auto" bgcolor="#FFE4E1">
    <h1>Final Exam Car Payment Calculator(CPC)</h1>
    
    <form>
    <table border="1" style="text-align:right;border-collapse:collapse">
     <tr>
      <td>Car Price: <input value="1000" name="price" /></td></tr> <!--default type is text, leave off if text-->
     
    <tr>
      <td>Interest rate: <input value="5.5" name="rate" /></td></tr>
    <tr>
      <td>Number of Years: 5 years (60 months)  </td></tr>
    <tr>
      <td>Down Payment: <input value="90" name="down" /></td></tr>
    <tr>
      <td>Monthly Payment: <input name="payment" onFocus="this.blur();" /></td></tr><!--Why is this blur? A: this blur becasue you don't get to decide how much to pay per month-->
    <tr>
      <td>paid after 5 years <input></td></tr>
    </table>
     <p>
     <input type="button" value="Calculate" onClick="calc(this)" /><input type="reset" value="Reset" />
    </form>
    
    <hr />
    <h3>Question #2</h3>
    Write a JavaScript function - calc() with parameter/argument to calculate a car payment:
    <ul><li>interest = rate / 100</li>
    
    <li>total = ((price - down) * (1 + interest))</li>
    <li>payment = total / 60 </li>
    </ul>
    
    </BODY></HTML>

  4. #4
    Join Date
    May 2010
    Posts
    2
    Thanks so much for your detailed reply! I think it will really help me, both for this problem and with javascript overall. I am going to study your answer and work on this calculation this afternoon.

  5. #5
    Join Date
    Nov 2012
    Posts
    4
    This is just amazing indeed. I really like it and appreciate to you about this work.
    This is the way to expose your ideas...Keep it up...

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 0.13628 seconds
  • Memory Usage 2,894KB
  • Queries Executed 15 (?)
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
  • (1)bbcode_html
  • (1)footer
  • (1)forumjump
  • (1)forumrules
  • (1)gobutton
  • (1)header
  • (1)headinclude
  • (1)headinclude_bottom
  • (5)memberaction_dropdown
  • (1)navbar
  • (4)navbar_link
  • (1)navbar_moderation
  • (1)navbar_noticebit
  • (1)navbar_tabs
  • (2)option
  • (5)postbit
  • (5)postbit_onlinestatus
  • (5)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 (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_postinfo_query
  • fetch_postinfo
  • 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