If you want to add your own style to the input such as chechkbox, radio and dropdown, you use the functions as shown below:

For adding style in checkbox:

 
    function customCheckbox(checkboxName){
        var checkBox = $('input[name="'+ checkboxName +'"]');
        $(checkBox).each(function(){
            $(this).wrap( "" );
            if($(this).is(':checked')){
                $(this).parent().addClass("selected");
                $(this).parent().next('label').addClass("selected");
            }
        });

        $(checkBox).click(function(){
            $(this).parent().toggleClass("selected");
            $(this).parent().next('label').toggleClass("selected");
        });
    }

You can customized the style class above based on your needs.
For radio type:

    function customRadio(radioName){
        var radio = $('input[name="'+ radioName +'"]');
        $(radio).each(function(){
            $(this).wrap( "" );
            if($(this).is(':checked')){
                $(this).parent().addClass("selected");
                $(this).parent().next('label').addClass("selected");
            }
        });

        $(radio).click(function(){
            $(radio).each(function(){
                if($(this).is(':checked')){
                    $(this).parent().addClass("selected");
                    $(this).parent().next('label').addClass("selected");
                } else {
                    $(this).parent().removeClass("selected");
                    $(this).parent().next('label').removeClass("selected");
                }
            });
        });
    }

    function customDropdown(dropdownId){
        var ddlWrapId = '#'+dropdownId+'_wrap';
        var dropdownId = '#'+dropdownId;
        var selectedInputId = '';
        var selectedTextId = '';

        $(document).on("click",ddlWrapId,function(){
            selectedInputId = '#'+$(ddlWrapId).find('input').attr('id');
            selectedTextId = '#'+$(ddlWrapId).find('span').attr('id');
            $(dropdownId).slideToggle();
        });
        
        $(document).on("click",ddlWrapId+" ul li",function(){
            if($(this).find('input').attr('name') === $(ddlWrapId).find('ul li input').attr('name')){
                $(selectedInputId).val($(this).find('input').val());
                var stateCounty = $(selectedInputId).val().split('#');
                $(selectedTextId).text(stateCounty[0]);
                $(selectedTextId).css("color","#333");
                $(this).parent().find('li.selected').removeClass('selected');
                $(this).addClass('selected');
            }
        });

        $('body').click(function(e){
            var clickedOn = $(e.target);
            if (!clickedOn.parents().andSelf().is(ddlWrapId)){
                $(dropdownId).hide('200');
            }
         });
    }

    function customTextBox(textBoxName){
        //get default value
        var textBoxValue = $("input[name='"+textBoxName+"']").val();
        
        //set input text empty on focus
        $(document).on("focus","input[name='"+textBoxName+"']",function(){
            if(this.value == textBoxValue){
                $(this).val('');
                $(this).css("color","#333");
            }
        });
        var buttonClicked = false;
        $("div[name='button']").hover(
            function () { buttonClicked = true; },
            function () { buttonClicked = false; }
        );
        //restore input text with default value on focusout
        $(document).on("focusout","input[name='"+textBoxName+"']",function(){
            if($(this).val() == '' && !buttonClicked){
                $(this).val(textBoxValue);
                $(this).css("color","#bfbfbf");
            }
        });
    }