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); 
}

Salesforce - SLDS Grid System

If you want one column, below code is helpful

 <div class="slds-grid slds-wrap">                                                 
                        <div class="slds-col slds-size_1-of-1 slds-small-size_1-of-1 slds-medium-size_1-of-1" style="padding:0px 2px">   
                            </div>
</div>






If you want two columns below code is helpful


<div class="slds-grid slds-wrap">                                                 
                        <div class="slds-col slds-size_1-of-1 slds-small-size_1-of-1 slds-medium-size_1-of-2" style="padding:0px 2px">   
                       //content goes here
</div>
  <div class="slds-col slds-size_1-of-1 slds-small-size_1-of-1 slds-medium-size_1-of-2" style="padding:0px 2px">   
                   //content goes here
                            </div>
</div>