Focus field if hash contains a field name, or focus previously edited field (ProcessWire admin)

pwFocusField.js

/**
 * Focus field on page edit screen if hash contains "field=fieldName",
 * or focus previously edited field using sessionStorage.
 * Eg. /admin/page/edit/?id=1051#focus=title
 */

// need to set before document.ready()
var focusFieldNameFromHash = getFocusFieldNameFromHash();


$(document).ready(function () {
    initFocusField();
});


function initFocusField() {
    var editedPageId = $("#PageIDIndicator").text();

    InputfieldFocus(getFocusField(focusFieldNameFromHash, editedPageId));
    setupFocusFieldEventListeners(editedPageId);
}

/**
 * Event listeners for field focus.
 */
function setupFocusFieldEventListeners(pageId) {
    $(document).on("change", "#ProcessPageEdit .InputfieldContent input, #ProcessPageEdit .InputfieldContent textarea, #ProcessPageEdit .InputfieldContent select", function () {
        sessionStorage.setItem("focusField", JSON.stringify({
            page: pageId,
            field: $(this).parents("li.Inputfield").first().attr("id").replace("wrap_Inputfield_", "")
        }));
    });
}

/**
 * Get focus field name set in location.hash, then remove.
 * @param {string} editedPageId
 * @returns void
 */
function getFocusFieldNameFromHash() {
    var fieldName = "",
        identifier = "focus=",
        hashValues;

    if (location.hash.indexOf(identifier) !== -1) {
        hashValues = location.hash.split(identifier);
        fieldName = hashValues[1];
        location.hash = location.hash.replace(identifier + fieldName, ""); // remove from hash
    }

    return fieldName;
}

/**
 * Get the field (wrapper) to set focus to.
 * 
 * @param {string} fieldName
 * @param {string} pageId
 * @returns jQuery object
 */
function getFocusField(fieldName, pageId) {

    if (fieldName === "" && location.href.indexOf("id=" + pageId !== 0)) {

        focusFieldSettings = sessionStorage.getItem("focusField");

        if (focusFieldSettings) {
            var settings = JSON.parse(focusFieldSettings),
                field = settings.field,
                page = settings.page;

            if (field && page) {
                fieldName = field;
            }
        }
    }

    return $("#wrap_Inputfield_" + fieldName);
}

Great, thanks, let me know if you find something. I haven't spent too much time deciding whether the "#focus=FIELDNAME" is the best solution for this, suggestions are welcome.