Php Programming Code Examples
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Builds JavaScript that updates the contents of one selector based on another.
Builds JavaScript that updates the contents of one selector based on another.
<HTML>
<HEAD>
</HEAD>
<BODY>
<?
/* To simulate database connectivity, I'll fill some arrays */
$store_id = array( "1", "3", "4", "5", "6");
$store_state = array( "California", "California", "California", "Nevada", "Utah");
$store_city = array( "Los Angeles", "San Francisco", "Walnut Creek", "Las Vegas", "Salt Lake City");
$numStores = 5;
$distinct_states = array( "California", "Nevada", "Utah");
/* create the javascript function the updates the city list */
echo "<SCRIPT Language=\"JavaScript\">\n";
echo "function UpdateCity()\n";
echo "{\n";
/* clear the city selector */
echo "\tvar City = document.choose_store.city.options.length;\n";
echo "\twhile(City > 0)\n";
echo "\t{\n";
echo "\t\tCity--;\n";
echo "\t\tdocument.choose_store.city.options[City].text = '';\n";
echo "\t\tdocument.choose_store.city.options[City].value = '';\n";
echo "\t}\n\n";
echo "\tdocument.choose_store.city.options[0].selected = true;\n\n";
/* figure out which state is selected*/
echo "\tvar StateSelected = 0;\n";
echo "\twhile(document.choose_store.state.options[StateSelected].selected==false) StateSelected++;\n\n";
$StoreState = "";
$CityCount = 0;
/* If this weren't a demo, I'd run a query something like: */
/* select * from store order by State */
/* But since this is a demo, I'll just read from an array */
$RowCount = 0;
while($RowCount < $numStores)
{
$store_ID = $store_id[$RowCount];
$store_State = $store_state[$RowCount];
$store_City = $store_city[$RowCount];
if($StoreState != $store_State)
{
if($StoreState != "")
{
echo "\t}\n";
}
echo "\tif(document.choose_store.state.options[StateSelected].value == '$store_State')\n";
echo "\t{\n";
echo "\t\tdocument.choose_store.city.options[0].value = 0;\n";
echo "\t\tdocument.choose_store.city.options[0].text = 'Choose a Store Location';\n\n";
$StoreState = $store_State;
$CityCount=1;
}
echo "\t\tdocument.choose_store.city.options[$CityCount].value = '$store_ID';\n";
echo "\t\tdocument.choose_store.city.options[$CityCount].text = '$store_City';\n\n";
$CityCount++;
$RowCount++;
}
echo "\t}\n";
echo "}\n";
echo "</SCRIPT>\n\n";
echo "<CENTER><FORM NAME=choose_store>";
echo "<SELECT NAME=state onChange=\"UpdateCity();\">\n";
/* This is another place I'd put a query: */
/* select distinct State from store order by State */
echo "<OPTION VALUE=0>Choose a State";
$RowCount = 0;
while($RowCount < count($distinct_states))
{
echo "<OPTION VALUE=\"";
echo $distinct_states[$RowCount];
echo "\">";
echo $distinct_states[$RowCount];
echo "\n";
$RowCount++;
}
echo "</SELECT>\n";
/* Now we need to know how many cities are listed for the state with the most stores */
/* select count(*) as items from store group by State order by items desc */
$MaxItems = 3;
echo "<SELECT NAME=city>\n";
$RowCount = 0;
while($RowCount <= $MaxItems)
{
echo "<OPTION VALUE=$RowCount>";
echo "Choose a Store Location\n";
$RowCount++;
}
echo "</SELECT><BR><BR>\n";
echo "</FORM></CENTER>";
echo "<SCRIPT Language=\"JavaScript\">UpdateCity();</SCRIPT>\n";
?>
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<BR>
</BODY>
</HTML>
