function js_positive(field, name)
{   
    if (document.getElementById(field).value.length==0)
        return true;
   
    if (document.getElementById(field).value.length>0 && isNaN(document.getElementById(field).value)) {
        document.getElementById(field).style.backgroundColor = "#FFCCFF";
        if (name=="")
            alert("This field must contain a numeric value.");
        else
            alert(name + " must contain a numeric value.");
        document.getElementById(field).focus();
        return false;
    }
    
    if (document.getElementById(field).value < 0) {
        if (name=="")
            alert("This field must contain a positive numeric value.");
        else
            alert(name + " must contain a positive numeric value.");
        document.getElementById(field).focus();
        return false;
    }
    

    document.getElementById(field).style.backgroundColor = "white";
    return true;
}


function js_positive_no_zero(field, name)
{   
    if (document.getElementById(field).value.length==0)
        return true;
   
    if (document.getElementById(field).value.length>0 && isNaN(document.getElementById(field).value)) {
        document.getElementById(field).style.backgroundColor = "#FFCCFF";
        if (name=="")
            alert("This field must contain a numeric value.");
        else
            alert(name + " must contain a numeric value.");
        document.getElementById(field).focus();
        return false;
    }
    
    if (document.getElementById(field).value <= 0) {
        if (name=="")
            alert("This field must contain a positive numeric value.");
        else
            alert(name + " must contain a positive numeric value.");
        document.getElementById(field).focus();
        return false;
    }
    

    document.getElementById(field).style.backgroundColor = "white";
    return true;
}