 Get the number of edited inputs |
| RainLover |
 Mar 5 2019, 08:19 AM
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#1
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Advanced Member  Group: Members Posts: 216 Joined: 16-November 09 Member No.: 10,346  |
Scenario
Every semester my students need to take at least one test. The following form gives the right average grade of a student: CODE <!DOCTYPE html> <html lang="en"> <head> <title>Average Grade</title> </head> <body> <form> Math: <input type="number" id="test1"> <input type="number" id="test2"> <input type="number" id="test3"> <output id="average"></output> <br> <input type="button" value="Calculate" id="calcBtn"> </form> <script> document.getElementById('calcBtn').addEventListener('click', function() { var test1 = document.getElementById('test1').value; var test2 = document.getElementById('test2').value; var test3 = document.getElementById('test3').value; var average = document.getElementById('average'); average.value = (Number(test1)+Number(test2)+Number(test3)) / 3; }); </script> </body> </html> The problem is it works right only if all the fields are edited. If the student doesn't take some tests, the average grade won't show the right value. I know it's because of dividing by the fixed number 3 when it calculates the average grade: CODE average.value = (Number(test1)+Number(test2)+Number(test3)) / 3; Question What is a simple approach to get the number of changed input fields? |
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Replies
| Christian J |
Mar 9 2019, 12:43 PM
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#2
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. Group: WDG Moderators Posts: 9,653 Joined: 10-August 06 Member No.: 7 |
You're welcome!
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Posts in this topic
RainLover Get the number of edited inputs Mar 5 2019, 08:19 AM
Christian J
If the student doesn't take some tests, the a... Mar 5 2019, 03:44 PM
RainLover
If the student doesn't take some tests, the ... Mar 5 2019, 10:34 PM Christian J Here's an idea:
Math:
<input type=... Mar 6 2019, 11:55 AM pandy Is checking for NaN really needed? Provided browse... Mar 6 2019, 03:40 PM Christian J
Is checking for NaN really needed? Provided brows... Mar 6 2019, 04:52 PM pandy No, it doesn't. I asked mainly because I wasn... Mar 7 2019, 05:52 AM Christian J Then again NaN is a tricky property that I don... Mar 7 2019, 06:10 AM Christian J Seems IE11 does need checking with isNaN(), since ... Mar 7 2019, 10:56 AM pandy Always IE, eh? Still.
Anyway, I have this page bo... Mar 7 2019, 05:30 PM Christian J I didn't understand that example either.
As ... Mar 8 2019, 06:16 AM Christian J Here's one with a regex instead of isNaN:
Mat... Mar 8 2019, 02:12 PM RainLover
Here's one with a regex instead of isNaN:
Ma... Mar 9 2019, 10:41 AM |
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