Firefox (Firefox) under JS set the CheckBox property checked= "Checked" is already available, but the check box does not show the reason for the tick

Just see the problem when the browser compatibility is the reason, ie, Google can display the normal.

After searching online, it was found that jquery's attr () method was inappropriate.

jQuery1.6 can be modified before using attr (), starting with jquery 1.6, the attr () method returns undefined properties that have not been set, and is set with prop () for settings of this type of checked.

Description of two methods given by Jquey official website:

Gets a property value that matches the first element in an element set, or sets one or more properties for each matching element.

It also points to retrieving and modifying DOM attributes, such as checked , selected or element states as elements, using the disabled . Prop () method.

JQuery API Detailed Description: https://api.jquery.com/attr/

Firefox (Firefox) under JS set the CheckBox property checked= "Checked" is already available, but the check box does not show the reason for the tick