JS Button active only if checkbox is True

Question

I would like to create a Detail Page JS button with the below (under the Lead object if it matters)

If A=TRUE and the button is pressed, update checkbox B to TRUE. If A=FALSE and the button is pressed, show Alert "Not the Right Case"

Really straight forward yet am having issues implementing. Any help is much appreciated.

var newRecords = []; 
var c = new sforce.SObject("Lead"); 
c.id ="{!Lead.Id}"; 


if ({!Lead.RedCarpetSignup__c}= true) 
{ 
c.{!Lead.Email_Verified_and_Activated__c} = true;
}


newRecords.push(c); 
result = sforce.connection.update(newRecords); 
window.location.reload();

Thanks.

Answer 1

Solution will be like this

{!REQUIRESCRIPT("/soap/ajax/31.0/connection.js")} 
var caseObj = new sforce.SObject("Case"); 
var CustomFieldValue = "{!Case.CustomField__c}"; 


if(CustomFieldValue==false) 
{ 
    alert("Not the Right Case"); 
}
else
{ 
    caseObj.CustomCheckbox__c = true;
    var result = sforce.connection.update([caseObj]);     
    location.reload();
}

Answer 2

you have to use the following strategy

{!REQUIRESCRIPT("/soap/ajax/31.0/connection.js")} if({! !your_Object_api_name__c.your_checkbox_api_name__c}){ alert('your custom message'); } else{ //update checkbox B to TRUE }