Unexpected Token Error on JavaScript Button

Question

I have the following code on a button

{!REQUIRESCRIPT("/soap/ajax/22.0/connection.js")}
{!REQUIRESCRIPT("/soap/ajax/22.0/apex.js")} 

if (({!Service_Call__c.Incomplete_Parts_Count__c} > 0))
{
alert( "Error: One or more parts on this call have not been completely filled out. Update parts before releasing." ); 
}
else {
var newRecords = []; 
var c = new sforce.SObject("Service_Call__c");
c.id ="{!Service_Call__c.Id}"; 
c.Release__c = true;
newRecords.push(c); 
result = sforce.connection.update(newRecords); 
window.location.reload();
}

It works as long as there is some type of number in that field, but sometimes it is just null and it causes this error. I've tried to manipulate my if statement to include the null, but I don't really know how. Any help would be appreciated. Thanks!

Answer 1

When possible, don't jump in and out of JavaScript; you can use normal formulas just like you would in Visualforce, which can reduce the likelihood of errors:

if( {!BLANKVALUE(Service_Call__c.Incomplete_Parts_Count__c,0) > 0} )

Upon evaluation, the JavaScript will be converted to a simple:

if( true )

or

if( false )