Question

I’m using the basic $.get() script for retrieving whether or not a record exists already in the database. The page called returns either yes or no depending if a record is found. Right now, it returns a blank value regardless.

This is the snippet of HTML with the specific input fields

<p><label for="participant_id">Please enter the Participant ID:</label>
    <cfinput type="text" name="participant_id" value="#attributes.stPages.Content.ParticipantId#" required="yes" message="Enter the Participant ID" />
    <cfif Len(trim(attributes.stPages.Content.ParticipantId)) eq 0>
        <cfinput type="button" name="checkunique" value="Check if Unique" />
        <cfinput type="hidden" name="participant_id_valid" value="false" />
    </cfif></p>

This is the calling script

$("#checkunique").click(function() {
    $.get('participant_id_check.cfm?participant_id=' + $('#participant_id').val(), function(data) {
        result = data.replace(/^\s+|\s+$/g,"");
        if (result) {
            $('#unique-result').text('Your Participant ID is accepted');
        } else {
            $('#unique-result').text('Your Participant ID has already been used.  Please enter another');
        }
    });
});

Here is the calling page. If I call it directly in the URL it works fine.

<!--- Check the database to ensure that the participant ID entered doesn't already exist (only for new entries). --->
<cfparam name="url.participant_id" default="" type="string" />

    <cfquery name="checkID" datasource="#APPLICATION.strConfig.datasource#">
        SELECT sessionid
        FROM tblsessions
        WHERE participant_id = <cfqueryparam cfsqltype="cf_sql_varchar" value="#url.participant_id#" null="no" />
    </cfquery>

    <!--- No record found; value is unique --->
    <cfif Not checkID.RecordCount>
        Yes 
    <cfelse>
        No <!--- Record found; value is not unique--->
    </cfif>

Answer 1

You are not using $.get correctly, try this:

$("#checkunique").click(function() {
    $.get('participant_id_check.cfm',
          {'participant_id': $('#participant_id').val()}, function(data) {
        result = data.replace(/^\s+|\s+$/g,"");
        if (result) {
            $('#unique-result').text('Your Participant ID is accepted');
        } else {
            $('#unique-result').text('Your Participant ID has already been used.  Please enter another');
        }
    });
});

Also a side point, you have nothing with the id='participant_id' so $('#participant_id').val() probably won’t get you anything