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help with script

P: 1
I need to make a script that will calculate the moon phase based on the moon's position... it's for an online game

here's what I've got - members locate the position by viewing the page source and it's always a number

then they would enter that number into an input box and submit it, which then would figure the answer one of 2 ways:

if the number is >=180, it subtracts 157.5 and then divides by 22.5, rounds the number and that's the answer

if the number is <180, it adds 202.5 and then divides by 22.5, rounds the number and that's the answer

I've posted on several different coding forums to try to get help: I wrote a script once before with lots of help from other people but I didn't know half of what I was doing or even what it all meant, just that it did what I wanted it to...

so on one forum someone posted this:

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  1. function calculate(position) {
  2.   var phase;
  3.   position = parseFloat(position);
  4.   if (position > 180) {
  5.      phase = Math.round((position - 157.5) / 22.5);
  6.      provideAnswer(phase);
  7.      }
  8.   else if (position < 180) {
  9.      phase = Math.round((position - 202.5) / 22.5);
  10.      provideAnswer(phase);
  11.      }
  12.   else {
  13.     var text = document.createTextNode("You must enter a number!");
  14.     document.getElementsByTagName("div")[0].appendChild(text);
  15.     }
  16.   }
  18. function provideAnswer(phase) {
  19.   // Do Something
  20.   }
and the html code was
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  1. <div>
  2.   <input type="text" id="position">
  3.   <input type="submit" onclick="calculate('position');">
  4. </div>
all that did was write You must enter a number! over and over again

then he said that the code was wrong and that calculate('position') should be calculate(document.getElementById('position').valu e) but when I changed the values in both the script and the html it just disabled it completely

please help?
Feb 23 '07 #1
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1 Reply

Expert Mod 15k+
P: 16,027
Expand|Select|Wrap|Line Numbers
  1. var pos = parseFloat(position);
then replace position in the if statements with pos.

You should also check for invalid numbers using isNaN(pos).
Feb 23 '07 #2

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