Question

144

Attach event listener through javascript to radio button

rated 0 times [ 151] [ 7] / answers: 1 / hits: 113616 / 13 Years ago, thu, january 19, 2012, 12:00:00

I have several radio buttons with the same name. Like this:

<form name=formA>

<input type=radio name=myradio value=A/>

<input type=radio name=myradio value=B/>

<input type=radio name=myradio value=C/>

<input type=radio name=myradio value=D/>

</form>

Now I have to add event listener through javascript to all the radio buttons. If the below pseudocode is wrong, then please tell me how to do it-

var radios = document.forms[formA].elements[myradio];

  for(radio in radios) {

    radio.onclick = function() {

        alert(radio.value);

    }

}

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3 Years ago

answered 13 Years ago pranavrorys · Accepted Answer

For in loops in JavaScript return the keys, not the values. To get the for in loop to work, assuming you haven't added custom properties to your array, you'd do:

for(radio in radios) {

    radios[radio].onclick = function() {

        alert(this.value);

    }

}

But you should always loop an array with a regular for loop to avoid accidentally including custom-added enumerable properties:

var radios = document.forms[formA].elements[myradio];

for(var i = 0, max = radios.length; i < max; i++) {

    radios[i].onclick = function() {

        alert(this.value);

    }

}