function insert(symbol) {
    var search = document.getElementById("search");
    var symbols = document.getElementById("symbols");

    search.value += symbol;
    symbols.style.visibility = "hidden";
}

function show() {
    var symbols = document.getElementById("symbols");
    symbols.style.visibility = "visible";
}

function insert_over(el) {
    el.style.color = "#ff0000";
}

function insert_out(el) {
    el.style.color = "#4d5763";
}

function insert_close() {
    var symbols = document.getElementById("symbols");
    symbols.style.visibility = "hidden";
}