text: var a
  function insert(val)
  {
      if (val == '+')
      {
        a=c
        
        document.getElementById("display").value="" 
      }else
      { 
      document.getElementById("display").value+=val
      var c=document.getElementById("display").value
      }    
  }
  
  
  function clear1()
  {
      document.getElementById("display").value=""
  }
  function equalp()
  {
      if(val== "=")
      {
  
          document.getElementById("display").value=""
      }
      else{
      val=document.getElementById("display").value
      result=eval(val)
      document.getElementById("display").value=result
      }
  }