How to calculate and return value from javascript?

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Hi guys, I got a problem about calculate a formula in the javascript. I want to calculate number from textbox and then process it in javascript. But the problem, it can't return any value to my page. Here's my code :

HTML

<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN"
    "http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd">
<html xmlns="http://www.w3.org/1999/xhtml" xmlns:v="urn:schemas-microsoft-com:vml">
  <head>
    <meta http-equiv="content-type" content="text/html; charset=UTF-8"/>
    <title>Google Maps JavaScript API Example: Extraction of Geocoding Data</title>
    
	<script>
		function gcd() 
		{
			var getlong1 = document.getElementById("long1").value;
			var getlat1 = document.getElementById("lat1").value;
			var getlong2 = document.getElementById("long2").value;
			var getlat2 = document.getElementById("lat2").value;
			
			var long1 = parseFloat(getlong1);
			var lat1 = parseFloat(getlat1);
			var long2 = parseFloat(getlong2);
			var lat2 = parseFloat(getlat2);
			
			
			var R = 6371; // km
			var a1 = lat1.toRadians();
			var a2 = lat2.toRadians();
			var Δφ = (lat2-lat1).toRadians();
			var Δλ = (long2-long1).toRadians();

			var a = Math.sin(Δφ/2) * Math.sin(Δφ/2) +
			Math.cos(a1) * Math.cos(a2) *
			Math.sin(Δλ/2) * Math.sin(Δλ/2);
			var c = 2 * Math.atan2(Math.sqrt(a), Math.sqrt(1-a));

			var d = R * c;
			
			document.getElementById('results').innerHTML = d;
		}
	</script>
	
	</head>

  <body>

    <form action="#" onsubmit="gcd(); return false;">
      <p>
		Lokasi 1 :
        <input type="text" name="long1" id="long1" size="40" />
        <input type="text" name="lat1" id="lat1" size="40" />
      </p>
	  <p>
		Lokasi 2 :
        <input type="text" name="long2" id="long2" size="40" />
        <input type="text" name="lat2" id="lat2" size="40" />
      </p>
	  <p>
		<input type="submit" name="find" value="Search" />
      </p>
    </form>
    <p id="results"></p>

  </body>
</html>

Anyone, can you help me? Thanks..

Posted 10-Dec-14 0:05am

Ananta Pratama

Updated 10-Dec-14 0:06am

v2

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Comments

Thanks7872 10-Dec-14 6:07am

There is nothing special in returning values from client side functions.


var s=your_function();
function your_function{
....
....
return Calculated_Value;
}

would work.

JR009 10-Dec-14 6:24am

do you get calculation result in variable d?

3 solutions

Solution 1

hi,

use

return d

before }

it might works

Posted 10-Dec-14 0:26am

mudgilsks

Solution 2

I have tried your solution guys become like this :

HTML

   "http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd">
<html xmlns="http://www.w3.org/1999/xhtml" xmlns:v="urn:schemas-microsoft-com:vml">
  <head>
    <meta http-equiv="content-type" content="text/html; charset=UTF-8"/>
    <title>Google Maps JavaScript API Example: Extraction of Geocoding Data</title>
    
	<script>
		function gcd() 
		{
			var getlong1 = document.getElementById("long1").value;
			var getlat1 = document.getElementById("lat1").value;
			var getlong2 = document.getElementById("long2").value;
			var getlat2 = document.getElementById("lat2").value;
			
			var long1 = parseFloat(getlong1);
			var lat1 = parseFloat(getlat1);
			var long2 = parseFloat(getlong2);
			var lat2 = parseFloat(getlat2);
			
			
			var R = 6371; // km
			var a1 = lat1.toRadians();
			var a2 = lat2.toRadians();
			var Δφ = (lat2-lat1).toRadians();
			var Δλ = (long2-long1).toRadians();

			var a = Math.sin(Δφ/2) * Math.sin(Δφ/2) +
			Math.cos(a1) * Math.cos(a2) *
			Math.sin(Δλ/2) * Math.sin(Δλ/2);
			var c = 2 * Math.atan2(Math.sqrt(a), Math.sqrt(1-a));

			var d = R * c;
			
			
						
			document.getElementById('results').innerHTML = d;
			return d;
		}
	</script>
	
	</head>

  <body>

    <form action="#" onsubmit="gcd(); return false;">
      <p>
		Lokasi 1 :
        <input type="text" name="long1" id="long1" size="40" />
        <input type="text" name="lat1" id="lat1" size="40" />
      </p>
	  <p>
		Lokasi 2 :
        <input type="text" name="long2" id="long2" size="40" />
        <input type="text" name="lat2" id="lat2" size="40" />
      </p>
	  <p>
		<input type="submit" name="find" value="Search" />
      </p>
    </form>
    <p id="results"></p>

  </body>
</html>

But it still can't work :(

Posted 10-Dec-14 0:34am

Ananta Pratama

v2

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Peter Leow · Accepted Answer · 2014-12-10T00:57:00

toRadians() is not defined. Try this:

C#

<script>
    function gcd()
    {
        var getlong1 = document.getElementById("long1").value;
        var getlat1 = document.getElementById("lat1").value;
        var getlong2 = document.getElementById("long2").value;
        var getlat2 = document.getElementById("lat2").value;

        var long1 = parseFloat(getlong1);
        var lat1 = parseFloat(getlat1);
        var long2 = parseFloat(getlong2);
        var lat2 = parseFloat(getlat2);

        var R = 6371; // km
            var a1 = lat1.toRadians();
        var a2 = lat2.toRadians();
        var lat_diff = (lat2-lat1).toRadians();
        var long_diff = (long2-long1).toRadians();

        var a = Math.sin(lat_diff/2) * Math.sin(lat_diff/2) +
        Math.cos(a1) * Math.cos(a2) *
        Math.sin(long_diff/2) * Math.sin(long_diff/2);
        var c = 2 * Math.atan2(Math.sqrt(a), Math.sqrt(1-a));

        var d = R * c;

        document.getElementById('results').innerHTML = d;
    }

           // Define toRadians()!!!
          if (typeof(Number.prototype.toRadians) === "undefined") {
                   Number.prototype.toRadians = function() {
                   return this * Math.PI / 180;
                   }
          }
</script>