Some confusing and uncommon attributes, hope they are useful_Basic knowledge

1. readonly [text password textarea]
Set the element to read-only mode, that is, it cannot be edited. Unlike disabled, readonly will not turn the characters into dark gray




2. defaultValue [all FORM elements]
His function is to return the content of the VALUE attribute when the element was initially set, that is,




3. defaultChecked [checkbox radio]
Same as defaultValue, its function is to return whether checkbox or radio is selected during initialization

4. indeterminate [checkbox]
Set checkbox to semi-selected Status
p.s. This attribute must be set through JS




5. hideFocus [all form elements] IE5.5
hide element focus The dotted line at the time, unlike onfocus=this.blur, uses hideFocus The element still maintains the focus state




6. UNSELECTABLE [All elements] IE5 .5
It prevents the element from being selected, that is, it keeps the previous element active. The special thing about this attribute is that it uses ON|OFF as the value of the attribute instead of true|false