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Question

I have 2 radio inputs. A,B

I an trying to make A as a selected radio by default. And I want the following behavior: when A get hidden then B should get checked by default.

This is what I tried. Please take a look.

<div >
     <input type="radio" checked="checked" value="0" name="a" />
     <strong>A</strong>
</div>
<div>
     <input type="radio" checked=""  value="1" name="b" />
     <strong>
     B
    </strong>
</div>
<input type="text" onfocus="Javascript:document.forms[1].opt_payment[1].checked=true;" maxlength="20" value=" " name="" />

Thanks

Answer 1

对 A 使用属性checked="checked" 。此外，如果您希望一次只检查 A 和 B 中的一个，请为它们提供相同的名称但不同的值。

Answer 2

checked="" means "Should be checked by default". There is no way to have the attribute present but indicate "not checked".

If you don't want a form control to be checked by default then do not include any checked attribute for it

Answer 3

<div >
     <input id="radioA" type="radio" checked="checked" value="0" name="a" />
     <strong>A</strong>
</div>
<div>
     <input id="radioB" type="radio" value="1" name="b" />
     <strong>
     B
    </strong>
</div>

Script:

if($("#radioA").is(":hidden")){
       $("#radioB").attr("checked","checked");
}

you can also use

$("#radioB").attr("checked",true);

or use prop for jquery version > 1.6

$("#radioB").prop("checked",true);