Example of setting radio value for eq in jQuery

I have never understood eq in jquery, but I found that eq is used in many places. I will share with you several examples below.

Definition and usage

: The eq () selector selects an element with the specified index value.

The index value starts from 0, and the index value of all the first element is 0 (not 1 ).

It is often used with other elements/selectors to select elements with specific sequence numbers in the specified group (in the preceding example ).

The Code is as follows:	Copy code
<P> <Label for = ""> Gender: </label> <Span> <Em> male </em> <Input type = "radio" name = "sex" value = "male"/> </Span> <Span> <Em> female </em> <Input type = "radio" name = "sex" value = "female"/> </Span> </P>

When jQuery sets the radio value, we can see that someone uses the nth method.

? Use nth

The Code is as follows:	Copy code
$ ('Input: radio [name = sex]: nth (0) '). attr ('checked', true );

In fact, nth and eq are the same and can be replaced with eq.

The Code is as follows:	Copy code
Var sex = 'female '; If (sex = 'male '){ $ ("Input: radio [name = 'sex ']: eq (0)"). attr ('checked', true ); } Else { $ ("Input: radio [name = 'sex ']: eq (1)"). attr ('checked', true ); }

In jQuery source code, we can see that nth is not recommended for use. If used, it will be converted to eq.

The Code is as follows:	Copy code
// Deprecated Expr. pseudo dos ["nth"] = Expr. pseudo dos ["eq"];