var maxfields = 20;    // Maximum upload fields
var defaultfields = 1; // Default upload fields
var fieldscount = 0;   // keep track of number of fields
var fieldsnumber = 0;  // give name to fields
var filecontainer;
var onloadFunctions = [];

function drtfileattach() {
    filecontainer = document.getElementById("fileattach_container");
    if (filecontainer)
        adduploadfields(defaultfields);
}


addOnLoadFunc(drtfileattach);


function adduploadfields(amount) {
    for (var i=0; i<amount; i++)
        adduploadfield();
}


function adduploadfield() {
    if (filecontainer && fieldscount < maxfields) {
        var newfield = document.createElement('div');
        newfield.style.marginTop = '4px';
        // Add input to DOM
        var newinput = document.createElement('input');
        newinput.type = "file";
        newinput.name= "file"+fieldsnumber;
        newinput.size = "50";
        newfield.appendChild(newinput);
        filecontainer.appendChild(newfield);
        fieldscount++;
        fieldsnumber++;
    }
}


function addOnLoadFunc (onloadFunction) {
    onloadFunctions[onloadFunctions.length] = onloadFunction;

    window.onload = function ( ) {
        for ( var i = 0; i < onloadFunctions.length; i++ ) {
            onloadFunctions[i]();
        }
    }
}