function validate_form ( )
{
    valid = true;

    if ( document.sellers.Name.value == "" )
    {
        alert ( "Please fill in the 'Name' box." );
        return false;
    } 
	

    if (document.sellers.Email.value == "" || document.sellers.Email.value.indexOf("@") == -1 || document.sellers.Email.value.indexOf(".") == -1 )
    {
        alert ( "Please fill in the 'Email' box with a valid email address." );
        return false;
    } 
	
	    if (isNaN(document.sellers.Phone.value) || document.sellers.Phone.value.length < 10)
    {
        alert ( "Please fill in the 'Phone Number' box with area code and no dashes or spaces." );
        return false;
    } 	
	
	    if ( document.sellers.WhatEquipment.value == "" )
    {
        alert ( "Please fill in the 'Equipment Description' box." );
        return false;
    } 

    if ( document.sellers.security_code.value == "" )
    {
        alert ( "Please enter a valid 'security code'." );
        return false;
    } 
	
    return valid;
}