Salesforce

<apex:actionStatus id="spinnerStatus">
              <apex:facet name="start">
                  <div role="status" class="slds-spinner slds-spinner_large slds-spinner_brand">
                    <span class="slds-assistive-text">Loading</span>
                    <div class="slds-spinner__dot-a"></div>
                    <div class="slds-spinner__dot-b"></div>
                  </div>
                </apex:facet>
   </apex:actionStatus>

LIGHTNING DESIGN SYSTEM


<apex:commandButton styleClass="slds-button slds-button_success" status="spinnerStatus" title="Save" value="Save" reRender="showmsg" action="{!save}" />