selectedIndex in a Select Box error

[Kevin Cornwell]

This is a autocomplete script that works with a textbox and a select box. It works fine for the most part, however when I clear the textbox (by back spacing, or delete button) it will load the select box with a blank entry (the select IS populated). When the script get to the bottom where I test for the selectedIndex value, it crashes ("Object doesn't support this property or method"). Even a alert crashes it. It seems to load the select with another option but without a index???

Suggestions?

Thanks,
Kevin C.

function autoComplete (field, select, property, forcematch) {
var found = false;
for (var i = 0; i < select.options.length; i++) {
    if (select.options[i][property].toUpperCase().indexOf(field.value.toUpperCase()) == 0) {
    found=true; break;
    }
}
if (found) { select.selectedIndex = i; }
else { select.selectedIndex = -1; }

    if (field.createTextRange) {
if (forcematch && !found) {
field.value=field.value.substring(0,field.value.length-1); 
            loadDetails(document.frmMain.selItem.options[document.frmMain.selItem.selectedIndex].value);
return;
}
var cursorKeys ="37;38;39;40;33;34;35;36;45;";
if (cursorKeys.indexOf(event.keyCode+";") == -1) {
var r1 = field.createTextRange();
var oldValue = r1.text;
var newValue = found ? select.options[i][property] : oldValue;
if (newValue != field.value) {
field.value = newValue;
var rNew = field.createTextRange();
rNew.moveStart('character', oldValue.length) ;
rNew.select();
}
}
}
 
//crashes on the following line when the select box is blank...
alert(document.frmMain.selItem.options[document.frmMain.selItem.selectedIndex].value);
 
    if (document.frmMain.selItem.options[document.frmMain.selItem.selectedIndex].value > 0){
        loadDetails(document.frmMain.selItem.options[document.frmMain.selItem.selectedIndex].value);
    }else{
        loadDetails(0);
    }
}
 

[Kevin Cornwell]

got it. on...

 
else { select.selectedIndex = -1; }
//changed to 
else { select.selectedIndex = 0; }