Salesforce - Mass delete records on list view

{!REQUIRESCRIPT('/soap/ajax/29.0/connection.js')} 
try 
{ 
var selectedRecords = {!GETRECORDIDS( $ObjectType.Lead )}; 
if(selectedRecords.length<1) 
alert('Please Select at Least One Row !'); 
else 
{ 
userConsent = confirm( 
selectedRecords.length + 
' Record(s) will be Deleted. Continue ? ' 
); 
if(userConsent == true) 
{ 
delResult = sforce.connection.deleteIds(selectedRecords); 
if (delResult[0].getBoolean("success")) 
{ 
alert('The Record(s) were Deleted Successfully.'); 
window.location.reload(); 
} 
else 
alert( 
'The Record(s) Could Not be Deleted. Error Message: ' + 
delResult[0].errors.message 
); 
} 
} 
} 
catch(e) 
{ 
alert('The Action Could not be Completed. Error Message: ' + e); 
}