Learn iframes and use them to solve cross-domain problems

Learn about iframes

The official definition is: iframe is HTML tag, which acts as a document in a document, or floatsframe (FRAME).The iframe element creates an inline frame (ie, an inline frame) that contains another document.

Simply understood as: iframe is an inline frame that can embed another document in the current HTML page.

iframe attributes

Only common attributes are introduced here

name: Specifies the name of the

We set an inline frame named ifr with a width of 600 and a height of 400, showing the border, hiding the slider, and showing the document as site b (you can also choose a local html document).We can write a text description in the iframe tag, because some low-version browsers do not support this tag, and when the document cannot be displayed, the text we wrote will be displayed on the page.

Open the browser to see the effect:

Get the content inside the iframe

Demonstrate the use of iframe

Resolving cross-domain issues

1. document.domain+iframe

This method can only be used for cross-domain requests between different subdomains under the same main domain, such as between a.com and 1.a.com, and between 1.a.com and 2.a.com.

Just point the document.domian of both pages to the main domain, such as document.domain="a.com".

The parent page embeds the child page through iframe, obtains the window of the child page through iframe.contentWindow, and then operates the child page, and the child page accesses the window of the parent page through parent.window and parent.

Write an example:

//Parent page http://a.com/a.html

//Subpage http://1.a.com/b.htmldocument.domain="a.com"var name2=2//Get the properties of the parent pagevar name11=parent.window.name1

2. window.name+iframe

The implementation is to pass data based on window.name.name is a property of the global window object in the browser environment.
When a new page is loaded in an iframe, the value of the name property remains the same.