Ajax

Ajax is an acronym for Asynchronous JavaScript And XML is a web development technique for creating interactive web applications. For more information about this new and exciting technology see Wikipedia.

Here is my example, please enter two QTH locators:

submit

The result will be displayed here.

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Behind the scenes of this example, i.e. on the server, is a PHP scrpit which handles the javascript response.

<?php
header ('Content-Type: text/plain');

require 'functions.php'; // Contains the QTH functions

$loc1 = strtoupper($_REQUEST['q1']);
$loc2 = strtoupper($_REQUEST['q2']);

loc2pos( $loc1, &$lat1, &$lng1 );
loc2pos( $loc2, &$lat2, &$lng2 );

if( checkloc( $loc1 ) && checkloc( $loc2 ) ) {
  distazim( $lat1, $lng1, $lat2, $lng2, &$dist, &$azim );
  printf( "Distance: %.0f km<br />Azimuth: %.0f&deg;\n", $dist, $azim );
} else {
  echo 'You have to enter <span style="color: #f00;">both '.
       "locators</span> correctly\n";
}
?>

Try calling the PHP script directly using various queries:

• calc.php (no queries)
• calc.php?q1=JO43LD&q2=FM18LV (Lilienthal to Washington)
• calc.php?q1=DM75AQ&q2=EN65GC (Santa Fe to Madison)

When you click on these links, the browser is displaying the server response which in the original example is replacing the text "The result will be displayed here."