//initial checkCount of zero 
var checkCount=1

//maximum number of allowed checked boxes 
var maxChecks=6

function setChecks(obj){ 
//increment/decrement checkCount 
if(obj.checked){ 
checkCount=checkCount+1 
}else{ 
checkCount=checkCount-1 
} 
//if they checked a 6th box, uncheck the box, then decrement checkcount and pop alert 
if (checkCount>maxChecks){ 
obj.checked=false 
checkCount=checkCount-1 
alert('Choose up to '+maxChecks+' checkboxes at a time.') 
} 
}