cffunction valitation error

Hi,

I have a form where I  fill a customer-no. into an input field and get the customer name using databinding.

This works fine, but when I put non-numeric values into customer-no I get following error:

Error invoking CFC customer.cfc : The CUST_ID argument passed to the getcustomer function is not of type numeric. [Enable debugging by adding 'cfdebug' to your URL parameters to see more information]

The message is correct, but how can I avoid to run the getcustomer function when the value is not numeric?

Here is my code:

The form:

<cfinput type="text" name="customer_no" style="width:140;background-color:yellow" maxlength="10"  validate="integer" validateat="onblur"   message="Customer No. format is integer">

<cfinput type="text" name="customer_name" style="width:170" maxlength="200" bind="cfc:customer.getcustomer({customer_no})" readonly="yes">

customer.cfc:

<cfcomponent >

<cffunction name="getcustomer" access="remote" returntype="string" output="yes"  >

    <cfargument name="cust_id"   type="numeric"  required="true" >

                 <cfset  r_customer = "">

         <cfquery name = "select_customer" dataSource = "x">

        SELECT name

        FROM customer

        WHERE id =  <cfqueryparam   cfsqltype="cf_sql_numeric" value="#arguments.cust_id#" >

        </cfquery>

<cfreturn r_customer>

</cffunction>

</cfcomponent>