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408

Chapter 16 Using HTML Forms

Figure 16 15 Radio buttons in HTML.

NAME

Unlike the 

NAME

 attribute of most input elements, this 

NAME

 is shared by 

multiple elements. All radio buttons associated with the same name are 

grouped logically so that no more than one can be selected at any given 

time. Note that attribute values are case sensitive, so the following 

would result in two radio buttons that are not logically connected.

Core Warning

Be sure the 

NAME

 of each radio button in a logical group matches exactly.

VALUE

The 

VALUE

 attribute supplies the value that gets transmitted with the 

NAME

 when the form is submitted. It doesn't affect the appearance of 

the radio button. Instead, normal text and HTML markup are placed 

around the radio button, just as with check boxes.

CHECKED

If the 

CHECKED

 attribute is supplied, then the radio button is initially 

checked when the associated Web page is loaded. Otherwise, it is ini 

tially unchecked.

ONCLICK, ONFOCUS, and ONBLUR

These attributes  supply JavaScript code to be executed when the but 

ton is clicked, receives the input focus, and loses the focus, respectively.

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