Tham số đầu tiên cho chức năng này là điểm bản đồ, bạn cũng tạo ra ở nơi khác dựa trên vĩ độ, kinh độ của vị trí và. Tham số thứ hai có chứa mã HTML mà bạn sẽ hiển thị bên trong cửa sổ pop-up | CHAPTER 14 THE DOM 219 for var i 0 i i alert theImages i .src script Accessing Elements Within a Form Another useful feature of the DOM is the ability to easily access elements within a form simply by using the element s name attribute on the form object. This can make validation of forms or accessing of different values very easy. For instance the following simple example will display a JavaScript alert box containing the value of the text input box. form id myForm input type text name foo value bar form script type text javascript var theForm myForm alert script Adding and Removing DOM Elements By controlling the DOM using JavaScript it is possible to add new elements to a web page without having to use a page refresh. This can be handy for creating elements such as menus tool tips and auto-complete features and is a little more advanced than the generic hide show method. While hiding and showing elements works well the ability to create manipulate and remove elements on the fly means that you do not have to create the elements from the start you can work with them as you see fit. Creating elements in JavaScript involves using the method. By passing in the type of element you want to create by referencing its HTML tag you can dynamically set up an element on the screen. You can then manipulate it however you see fit. The following snippet shows how this can be accomplished style type text css .newdiv background f00 border 1px solid 000 width 50px height 50px style 220 CHAPTER 14 THE DOM a href onclick createDiv Create a div a script type text javascript Function to create a new div element. function createDiv Create the div. var mydiv div Set the div s class. newdiv Append the div to the body. mydiv script As you can see there are several steps involved in creating a new element to add to your HTML page. First you .
