<apex:commandButton onclick="insert_numbers()" action="{!save}"
                value="Insert Numbers and Save" rerender="mytable" />
<apex:commandButton value="CLICK TO CREATE ORDER" action="{!post}" disabled="{!hide}" >

public PageReference save() {
         update ob;
         refreshPage=true;
         return null;
        }
      public void post(){
            HttpRequest req = new HttpRequest();
            HttpResponse res = new HttpResponse();
            Http http = new Http();
            req.setMethod('POST' ); // Method Type