JavaScript study notes (14) Introduction to the use of window objects_Basic knowledge

1. Window position
The following is the position of the browser window from the left and top of the screen

Copy the code The code is as follows:

var leftPos = (typeof window.screenLeft == "number") ? window.screenLeft : window.screenX; //Left position
var topPos = (typeof window.screenTop == "number" ) ? window.screenTop : window.screenY; //Top position

2. Browser size
below to get the size of the browser page viewport

Copy code The code is as follows:

var pageWidth = window.innerWidth,
pageHeight = window.innerHeight;

if (typeof pageWidth != "number") {
if (document.compatMode == "CSS1Compat") {
pageWidth = document.documentElement.clientWidth;
pageHeight = document.documentElement.clientHeight;
} else {
pageWith = document.body.clientWdith;
pageHeight = document.body.clientHeight;
}
}

3. Open or pop-up window
The window.open() method can accept 4 parameters. Usually you only need to specify the first parameter. The first parameter is the URL, and the second parameter is _self, _parent, _top, _blank or the frame name

Copy code The code is as follows:

window.open("http://www.baidu.com" );
window.open("http://www.baidu.com","_blank");
window.open("http://www.baidu.com","topFrame"," height=400,width=400,top=10,left=10,resizable = yes");
topFrame.resizeTo(500,300); //Adjust the window size
topFrame.moveTo(100,100); //Move Window position
topFrame.close(); //Close the newly opened window, IE will report an error

4.location object
location.href(URL) Load URL

Copy code The code is as follows:

location.href(URL) Load URL
location.href(" http://www.baidu.com");
location.href = "http://www.baidu.com" ; //Same as above
location.assign = "http://www.baidu. com"; //Same as above
window.loaction = "http://www.baidu.com"; //Same as above
location.replace("http://www.baidu.com"); // Same as above, but cannot go back

location.reload(); //Reload (maybe loaded from cache)
location.reload(true); //Reload (loaded from server)

location.search() returns the query string in the URL. What does the string mean? Beginning with

5. Get the query string parameters

Copy the code The code is as follows:

function getQueryStringArgs() {
var qs = (location.search.length > 0) location.search.substring(1) : "";
var args ={};
var items = qs.split("&");
var item = null,name = null,value = null;
for (var i=0 ; i{
item = itmes[i].split("=");
name = decodeURIComponent(item[0]);
value = decodeURIComponent(item[1]);
args[name] = value;
}
return args;
}

//Assume the query string parameter is?q=javascript&num=10
var args = getQueryStringArgs();
alert(args["q"]); //"javascript"
alert(args["num"]); //"10"

6.history object

Copy code The code is as follows:

history.go() page jump
history.go(- 1); //Go back one page
history.go(1); //Go one page forward
history.go(2); //Go two pages forward
history.go("baidu.com" ); Jump to the nearest baidu.com page

history.back(); //Back one page
history.forword(); //Forward one page

Detect whether the current page is the first page opened by the user

Copy the code The code is as follows:

if (history.length == 0) {
//If the first page is opened, perform certain operations
}

7. Page loading
window.onload() is used to perform certain operations after the page is loaded

Copy code The code is as follows:

window.onload = function () {
//Perform some operations
}