function Validate(frm)
{
	var flag; 
	if (frm.txtYourName.value == "")
    {
    	alert('Please enter your name');
        frm.txtYourName.focus();
        return false;
    }
    else if (frm.txtYourEmail.value == "")
    {
    	alert('Please enter your e-mail address');
        frm.txtYourEmail.focus();
        return false;
    }
    else if (frm.txtColName.value == "")
    {
    	alert('Please enter your colleague name');
        frm.txtColName.focus();
        return false;
    }
    else if (frm.txtColEmail.value == "")
    {
    	alert('Please enter your colleague e-mail address');
        frm.txtColEmail.focus();
        return false;
    }
}