var JSONService = function() {
    this.getEl = function(id) {
        return document.getElementById(id);
    };
    this.unloadScript = function(idScript) {
        var elementHead = document.getElementsByTagName("head").item(0);
        var elementScript = this.getEl(idScript);
        if (elementScript) {
            elementHead.removeChild(elementScript);
        }
    };
    this.loadScript = function(idScript, urlScript) {
        this.unloadScript(idScript);
        var elementHead = document.getElementsByTagName("head").item(0);
        var elementScript = document.createElement("script");
        elementScript.setAttribute("id", idScript);
        elementScript.setAttribute("type", "text/javascript");
        elementScript.setAttribute("charset", "utf-8");
        elementScript.setAttribute("src", urlScript);
        elementHead.appendChild(elementScript);
    };
};