function validate_contact() {

if ( document.getElementById('name').value.length < 2 ) {
    alert("Please provide a real name");
    return false;
    }

if (document.getElementById("address").value.indexOf('@')==-1  || document.getElementById("address").value.indexOf('.')==-1  || document.getElementById("address").value.length <= 7 )
    {
    alert("Please provide your email");
    return false;
    }

if ( document.getElementById('phone').value.length < 5 ) {
    alert("Please provide a phone number");
    return false;
    }


if (document.getElementById("enquiry").value.length < 5 )	{
    alert("Please write a message ");
    return false;
    }
}


function show_the_price(id){
if ( id=='min_truck' )  document.getElementById('show_price').style.background="url('images/price_mintruck.jpg') no-repeat bottom left";
if ( id=='quart_truck' )  document.getElementById('show_price').style.background="url('images/price_quartruck.jpg') no-repeat bottom left";
if ( id=='half_truck' )  document.getElementById('show_price').style.background="url('images/price_halftruck.jpg') no-repeat bottom left";
if ( id=='threequart_truck' )  document.getElementById('show_price').style.background="url('images/price_threequartruck.jpg') no-repeat bottom left";
if ( id=='max_truck' )  document.getElementById('show_price').style.background="url('images/price_maxtruck.jpg') no-repeat bottom left";
}

function show_the_price_full(id){
if ( id=='min_truck' )  document.getElementById('show_price').style.backgroundPosition="top left";
if ( id=='quart_truck' )  document.getElementById('show_price').style.backgroundPosition="0px -269px";
if ( id=='half_truck' )  document.getElementById('show_price').style.backgroundPosition="0px -538px";
if ( id=='threequart_truck' )  document.getElementById('show_price').style.backgroundPosition="0px -807px";
if ( id=='max_truck' )  document.getElementById('show_price').style.backgroundPosition="bottom left";
}