jquery decision checkbox is selected

In the HTML checkbox, the selected word will have attributes checked= "checked".

If a checkbox is selected, the value alert ($ "#xxx" for the CheckBox's property "Checked") is printed "true" instead of "checked" attr ("checked").

If not selected, print out "undefined". That's weird, isn't it? Keep looking!

Don't try to make such judgments:

The code is as follows	Copy Code
if ($ "#xxx". attr ("checked") = = "true")

Because it is wrong to do so, the jquery API manual writes that the return value of attr (name) is object.

So, it should be if ($ "#xxx". attr ("checked") ==true)

Instance

code is as follows

copy code

<input type= "checkbox" Name= "Choiceid" id= "Choiceid" value= "001" " <input type=" checkbox "Name=" Choiceid "id=" Choiceid "value=" "002" <input type= "checkbox" Name= "Choiceid" id= "Choiceid" value= "003" Method One: If ($ ("#choiceId") get (0). checked) {//Do something} method two: if ($ (' #choiceId). Is (': Checked ')) {//Do somethin G} Method Three: if ($ (' #choiceId). attr (' checked ')) {//do something}