JavaScript study notes (10)_javascript skills

Window对象
window对象表示整个浏览器窗口，window还可用于移动或调整它表示的浏览器的大小。

一、窗口操作
window.moveBy(dx,dy)

把浏览器窗口相对当前位置水平移动dx个像素，垂直移动dy个像素。dx值为负数，向左移动窗口，dy值为负数，向上移动窗口。

window.moveTo(x,y)

移动浏览器窗口，使它的左上角位于用户屏幕的(x,y)处。可以使用负数，不过这样会把部分窗口移出屏幕的可视区域。

window.resizeBy(dw,dh)
相对于浏览器窗口的当前大小，把它口的宽度调整dw个像素，高度调整dy个像素。dw为负数，把缩小窗口的宽度，dy为负数，缩小窗口的高度。
window.resizeTo(w,h)
把窗口的宽度调整为w，高度调整为h。不能使用负数。窗口在屏幕上的位置以及它的尺寸。由于缺乏相应的标准，就产生了问题。

二、导航和打开新窗口
window.open()方法打开新窗口

该方法接收四个参数：①载入新窗口的URL ②新窗口的名字（为目标所用） ③特性字符串 ④说明是否用新载入的页面替换当前载入的页面的Boolean值。

第三个参数特性字符串的设置列表：

设置	值	说明
left	Number	新创建的窗口的左坐标，不能为负数*
top	Number	说明新创建的窗口的上坐标。不能为负数*
height	Number	设置新创建的窗口的高度。该数字不能小于100*
width	Number	设置新创建的窗口的宽度。该数字不能小于100*
resizable	yes,no	判断新窗口能否拖动边线调整大小，默认值是no
scrollable	yes,no	判断新窗口是否允许滚动，默认值是no
toolbar	yes,no	判断新窗口是否显示工具栏，默认值是no
status	yes,no	判断新窗口是否显示状态栏，默认值是no
location	yes,no	判断新窗口是否显示地址栏，默认值是no

Note: Feature strings are comma separated, so there can be no spaces before or after the comma or equal sign.

The window.open() method will return the window object as its function value. The window object is the newly created window (or the frame if the given name is the name of an existing frame). With this object, you can operate the newly created window.

3. System dialog box

No need to write more about this. alert(), confirm(), prompt()

4. Status bar

The status bar tells the user when the page is loading and when the page has been loaded. It can be controlled through two properties of the window: status and defaultStatus

defaultStatus is used to define the default display content of the browser status bar, but when the mouse moves over the link, the text of the status bar will change, and when the link is moved out, it will change to the value defined by defaultStatus. This is different from the status attribute which is used to temporarily change the content of the status bar.

5. Time interval and pause

setTimeout() receives two parameters. The first parameter can be a code string or a function pointer. The second parameter is the number of milliseconds to wait before executing it (1/1000 seconds).

To pause and cancel, call the clearTimeout() method. This method receives a parameter "numeric pause ID". The digital pause ID is created by setTimeout(). setTimeout() returns a numeric pause ID, which is similar to the process ID in the operating system. The pause ID is essentially the ID of the process to be delayed.

6. History

The go() method has only one parameter, which is the number of pages forward or backward. If it's a negative number, go back in the browser history, if it's an integer, go forward.

window.history.go(-1); //Go back one page

window.history.go(1); //Forward one page

or

history.go(-1); //The reference to the window object is not required

The same operation can be achieved using the back() method and forward() method:

history.back(); //Go back one page

history.forward(); //Forward one page

Use the length attribute to view the number of pages in history:

alert(history.length);

If you want to go forward or back multiple pages, you can use the length attribute to see if you can do this first.