What are the canvas keyboard events?

Canvas keyboard events include keydown event, keyup event, keypress event, input event, focus event and blur event, etc. Detailed introduction: 1. keydown, triggered when the user presses any key on the keyboard. You can use the keyCode or key attribute of the event object to obtain the information of the pressed key. The keyCode attribute returns a number indicating the pressed key. The key code, the key attribute returns a string indicating the name of the pressed key, etc.

# Operating system for this tutorial: Windows 10 system, Dell G3 computer.

Canvas is a new tag in HTML5, used to draw graphics and animations on web pages. In Canvas, JavaScript can be used to control the drawing and interaction of graphics. Keyboard events are one of the common interaction methods. By capturing the user's key operations on the keyboard, various keyboard-related interactive effects can be achieved.

Canvas keyboard events mainly include the following:

keydown event: triggered when the user presses any key on the keyboard. You can use the keyCode or key property of the event object to obtain information about the pressed key. The keyCode property returns a number representing the keycode of the pressed key, and the key property returns a string representing the name of the pressed key.

Keyup event: Triggered when the user releases a key on the keyboard. You can also use the keyCode or key attribute of the event object to obtain information about the released key.

keypress event: Triggered when the user presses a character key on the keyboard. Similar to the keydown event, you can use the keyCode or key property of the event object to obtain information about the pressed key. However, the keypress event will only be triggered on the keys that input characters. The keypress event will not be triggered for control keys (such as Shift, Ctrl, Alt, etc.).

Input event: Triggered when the user enters text in the input box. You can use the target attribute of the event object to obtain the input box element that triggered the event, and use the value attribute to obtain the text content in the input box.

focus event: Triggered when the user moves focus to the Canvas. You can use the target attribute of the event object to get the Canvas element that triggered the event.

blur event: triggered when the Canvas loses focus. You can also use the target attribute of the event object to get the Canvas element that triggered the event.

Through these keyboard events, we can achieve some interesting interactive effects, such as character control in the game, real-time verification during form input, etc. These keyboard events can be flexibly used to achieve various interactive effects according to different scenarios and needs.

It should be noted that Canvas itself does not have a built-in keyboard event handling mechanism, so JavaScript code needs to be used to monitor and handle these keyboard events. In the event handling function, you can perform corresponding operations based on the information of the pressed key, such as changing the position, size or color of the graphic, etc.

To summarize, Canvas keyboard events mainly include keydown, keyup, keypress, input, focus, blur, etc. By monitoring and processing these events, various keyboard-related interactive effects can be achieved. As a programmer, we need to rationally use these keyboard events according to specific needs and scenarios to achieve the interaction effects expected by users.

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