Invalid left hand side in custom Javascript

Question

I'm trying to edit a custom OnClick JS button which creates a PDF from a quote, provided the quote passes certain checks.

this code works:

{!REQUIRESCRIPT("/soap/ajax/29.0/connection.js")} 
var q = new sforce.SObject("Quote"); 
q.id = "{!Quote.Id}"; 
q.Status = "Presented"; 
result = sforce.connection.update([q]); 

if('{!Quote.Status}'!= 'Cancelled'&&{!ISNULL(Quote.Invoice_Address_Lines__c)=FALSE}&&{!ISNULL(Quote.Invoice_Address_Country__c)=FALSE}) 
{ 
do some business logic here... 
var isOk = true; 
} if(isOk) 
{ 
var pdfOverlay = QuotePDFPreview.quotePDFObjs['quotePDFOverlay']; 

pdfOverlay.dialog.buttonContents = "<input value=\'Save to Invoice Overview\' class=\'btn\' name=\'save\' onclick=\"QuotePDFPreview.getQuotePDFObject(\'quotePDFOverlay\').savePDF(\'0\',\'0\');\" title=\'Save to Quote\' type=\'button\' ><input value='Save and Email' class='btn' name='saveAndEmail' onclick=\"QuotePDFPreview.getQuotePDFObject(\'quotePDFOverlay\').savePDF(\'1\');\"; title='Save and Email Quote' type='button' ><input value=\'Cancel\' class=\'btn\' name=\'cancel\' onclick=\"QuotePDFPreview.getQuotePDFObject(\'quotePDFOverlay\').close();\" title=\'Cancel\' type=\'button\' >"; 

//change this to use the correct template for your business/environment!! 
//TB: This has been adapted to choose the correct template based on the result Quote_Template_ID__c returns 
pdfOverlay.summlid = '{!Quote.Quote_Template_ID__c}'; 

pdfOverlay.setSavable(true); 

//change this to use the quote id 
pdfOverlay.setContents('/quote/quoteTemplateDataViewer.apexp?id= {!Quote.Id}','quote/quoteTemplateHeaderData.apexp?id={!Quote.Id}'); 

pdfOverlay.display(); 
} 
else 
{ 
//raise an alert to let the user know about some business rule 
alert('Invoices must have an Address and Country specified and cancelled Invoices cannot be regenerated.'); 
}

I need to edit the initial "if" to add a check for a situation where the invoice in question is marked as needing a VAT number (VAT_Number_Invoice__c) AND the VAT number (VAT_Number__c) is blank.

I'm replacing

if('{!Quote.Status}'!= 'Cancelled'&&{!ISNULL(Quote.Invoice_Address_Lines__c)=FALSE}&&{!ISNULL(Quote.Invoice_Address_Country__c)=FALSE}) 
{ 

with

if(
'{!Quote.Status}'!= 'Cancelled'&&
{!ISNULL(Quote.Invoice_Address_Lines__c)=FALSE}&&
{!ISNULL(Quote.Invoice_Address_Country__c)=FALSE}&&
(
{!ISNULL(Quote.VAT_Number__c)=FALSE} ||
'{!Quote.VAT_Number_Invoice__c}' = 'FALSE')
)
{

or variations on this. I cant seem to get past left hand side alignment errors, or the code just not picking up the last condition.

Has anyone got any ideas how to get this code working? Am I doing anything obviously wrong?

essentially: build the PDF if (1 isnt blank AND 2 isnt blank AND 3 isnt blank AND (4 isnt blank OR 5 is false))

Answer 1

I always recommend evaluating your conditions within the merge field, which reduces the probability of errors. Here's a revised if statement:

if({!NOT(ISPICKVAL(Quote.Status,'Cancelled'))&&
    NOT(ISBLANK(Quote.Invoice_Address_Lines__c))&& 
    NOT(ISBLANK(Quote.Invoice_Address_Country__c))&&
    (NOT(ISBLANK(Quote.VAT_Number__c)) ||
     NOT(Quote.VAT_Number_Invoice__c))}) {

Using this method will force compiler errors when you try to save the code, which prevents trivial mistakes, and eliminates the various errors you might get when using merge syntax with semi-complicated JavaScript.

Answer 2

Replace your if condition as below

if(
'{!Quote.Status}' != 'Cancelled' &&
{!NOT(ISNULL(Quote.Invoice_Address_Lines__c))} &&
{!NOT(ISNULL(Quote.Invoice_Address_Country__c))} &&
({!NOT(ISNULL(Quote.VAT_Number__c))} || '{!Quote.VAT_Number_Invoice__c}' == 'FALSE')
)

From the above if condition, you want to check if Quote.VAT_Number_Invoice__c is not False.

('{!Quote.VAT_Number_Invoice__c}' = 'FALSE') will basically process the expression within the curly braces, hence it was trying to assign the value which is incorrect, whereas

('{!Quote.VAT_Number_Invoice__c}' == 'FALSE') will check if it false or not. For string comparison in javascript, use == instead of =

Refer VisualForce functions for more info.