// Текущая страница:  /eazy-1.html?aa=11&bb=22
    ret = BookJsHelper.getQueryParam()
    // ret => {aa:'11',bb:'22'}
    ret = BookJsHelper.getQueryParam('cc','33')
    // ret => '33'
    ret = BookJsHelper.getQueryParam('dd','444','/some?dd=44')
    // ret => 44

    ret = BookJsHelper.showMsg(msg)
    // ret => 'id-xxxxxx' идентификатор сообщения

ret = BookJsHelper.tag(
         'select',
         {class:'form-control',name:'type',data:{aa:1,bb:2}},
         [
               ['option',{value:"2"},"Вариант 2"],
               ['option',{value:"1"},"Вариант 1"]
         ]
     );

// ret => <select class="form-control" name="type" data-aa='1' data-bb='2'><option value="2">Вариант 2</option><option value="1">Вариант 1</option></select>

data = {a1:{a2:111},b1:[{b2:222}]};

// BookJsHelper.dataPath('a1.a2',data) => 111
// BookJsHelper.dataPath('a1.a2.a3',data) => null
// BookJsHelper.dataPath('a1.a2.a3',data,123) => 123
// BookJsHelper.dataPath('b1[0].b2',data) => 222