TextRange object processing in text section _ javascript skills

TextRange is an object used to represent the text in HTML elements. It is an object used to process part of JavaScript Object text because the user request side is tied to the TextRange object, an object used to process part of the JavaScript Object text.

TextRange is an object used to express text in HTML elements. Although we do not usually use this object, it is provided in IE4.0. However, the call methods provided by TextRange are obscure, so what can we do with it?
The traditional use of TextRange is to circle text content on web pages, such as changes, deletions, and additions. However, its classic purpose is to search for text on the Web page (which is relatively simple) and obtain the cursor position of the input box. The latter can be used to derive many more useful functions. For example, to restrict the input of MaskTextBox, the core technical point is to obtain the cursor position of the input box, and then use a regular expression to judge the input content. In addition, I will introduce "natural navigation using arrow keys in the input box matrix". The core technical point is to obtain the cursor position in the input box.

The entire code for getting the cursor position in the input box is actually very short, but these objects and methods are not very commonly used.

Js Code