New Javascripter

**sean2me** · 06:00 AM

I am trying to learn Javascript on my own, its proving sneaky and difficult! When I run the code pasted below, I get errors such as "object expected". I don't know what that means, or how to fix it. It seems my variables are all good, it then seems my problem is the return function.

I am trying to return a value to the azimuth and distance input boxes (is that possible?)

Also, I am noticing different types of javascript, one being a standard type, the other being DOM (have I got that right). I was wondering if I am mixing types without knowing, and maybe creating incompatible coding?

I am also curious about how to calculate. For instance I understand Math.sqrt() is a squareroot function, however my browser states that Math is undefined?? If anyone can help set me straight on this, it would be most appreciated! I must be close, I just need someone to push me over!!

Code:

<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<html>
<head>
<script type="javascript">
function DELTA(north1,north2,east1,east2)
  {
  var north1=Number(north1)
  var north2=Number(north2)
  var east1=Number(east1)
  var east2=Number(east2)
  dN=north2-north1
  dE=east2-east1
  alert(dN + " "+ dE)
  }
function AZIMUTH_CALC(north1,north2,east1,east2)
  {
  var north1=Number(north1);
  var north2=Number(north2);
  var east1=Number(east1);
  var east2=Number(east2);
  var AZ=(east2-east1)/(north2-north1)
  alert(AZ)
  return(AZ)
  }
</script>
<script type="javascript">
function DISTANCE_CALC(north1,north2,east1,east2)
  {
  var north1=Number(north1)
  var north2=Number(north2)
  var east1=Number(east1)
  var east2=Number(east2)
  var DIST=Math.sqrt(((east2-east1)^2)+((north2-north1)^2));
  alert(DIST);
  return(DIST);
  }
</script>
<script type="javascript">
function inverse1()
  {
  north1=document.FORM_1.north1.value;
  north2=document.FORM_1.north2.value;
  east1=document.FORM_1.east1.value;
  east2=document.FORM_1.east2.value;
  alert("Azimuth = " + AZIMUTH_CALC(north1,north2,east1,east2) + " Distance = " + DISTANCE_CALC(north1,north2,east1,east2))
  }
</script>
<meta http-equiv="Content-Type" content="text/html; charset=iso-8859-1">
<title>COORDINATE INVERSE</title>
</head>
<body>
<form method="post" name="FORM_1" target="_self" id="FORM_1">
  <table width="200" border="0" summary="Calculate simple inverse between two points.">
    <caption align="top">
      Coordinate Entry
    </caption>
    <tr>
      <th scope="col">&nbsp;</th>
      <th scope="col"> Point # 1 </th>
      <th scope="col">Point # 2 </th>
    </tr>
    <tr>
      <th scope="row"><div align="right">Northing</div></th>
      <td><input type="text" name="north1" value="750000" tabindex="1"></td>
      <th scope="col"><input type="text" name="north2" value="700000" tabindex="3"></th>
    </tr>
    <tr>
      <th scope="row"><div align="right">Easting</div></th>
      <td><input type="text" name="east1" value="550000" tabindex="2"></td>
      <th scope="col"><input type="text" name="east2" value="500000" tabindex="4"></th>
    </tr>
  </table>
  <p>
    <input name="button" type="button"  tabindex="5" value="CALC" onClick="inverse1(north1,north2,east1,east2)">
  </p>
  <p>
    <label for="textfield">Azimuth: </label>
    <input type="text" name="AZIMUTH_CALC" id="AZIMUTH_CALC" value="AZ" tabindex="6" border="0">
    <label for="label">Distance: </label>
    <input type="text" name="DISTANCE_CALC" id="DISTANCE_CALC" value="DIST" tabindex="7" border="0">
  </p>
</form>
</body>
</html>

**mgraphic** · 03-06-2008, 12:27 AM

Use FireFox for debugging JavaScript code because the Error Consol on FF is the best to use as it will give you line numbers and hilite offending errors in the source code.