function submitData()
{

    var username = document.getElementById('name').value;
    var address = document.getElementById('address').value;
    var phoneno = document.getElementById('phoneno').value;
    var bestcalltime = document.getElementById('best_call_time').value;
    var banner=document.getElementById('banner_id').value;
    
     if(username=='' && address!='' && phoneno!='')
    {
        document.getElementById('splash').style.display='';
        document.getElementById('name').focus;
        return false;
    }
    if(username!='' && address=='' && phoneno!='')
    {
        document.getElementById('splash').style.display='';
        document.getElementById('address').focus;
        return false;
    }
    if(username=='' && address=='' && phoneno!='')
    {
        document.getElementById('splash').style.display='';
        document.getElementById('phoneno').focus;
        return false;
    }
    if(username=='' && address=='' && phoneno=='')
    {
        document.getElementById('splash').style.display='';
        document.getElementById('name').focus;
        return false;
    }
    var url='';
    if(username!='' && address !='' && phoneno!='')
    {
      document.getElementById('splash').style.display='none'; 
 	  url= site_host_url+'advertiser/payperlead/name/'+username+'/address/'+address+'/phone/'+phoneno+'/call_time/'+bestcalltime+'/bid/'+banner+'/sid/'+Math.random();
 	
	   request.open("GET",url,true);
	   request.setRequestHeader('Content-Type',  "text/xml");
        request.onreadystatechange =function handleResponse()
        {
            if(request.readyState == 4 || request.readyState=='complete')
            {		
            if(request.responseText!='')			
            {
                document.getElementById('splash').style.display='none'; 
                document.getElementById('successMsg').style.display='';
                document.getElementById('name').value='';
                document.getElementById('address').value='';
                document.getElementById('phoneno').value='';
                document.getElementById('best_call_time').value='';
            }
            }
        }
	
	}
	request.send(null);
}
<!--end of function submitData-->

function validateForm()
{
    var username = document.getElementById('name').value;
    var address = document.getElementById('address').value;
    var phoneno = document.getElementById('phoneno').value;
   
}
<!--end of function validateForm-->