Question

I wrote this code to switch between radio buttons and show my custom alert.

<script>
    function test() {
            if (radio[0].checked = true) {
                alert("hello1");
            }

            if (radio[1].checked = true) {
                alert("hello2");
            }
    }
</script>


<input type="radio" onclick="test()" value="0">
<input type="radio" onclick="test()" value="1">

When check any of radio buttons it must show specific alert.
What is wrong?

Answer 1

Two things you need to take note here:
1) You must use the ‘name’ attribute in the radio button. Otherwise you won’t be able to check the radio button.
2) You cannot use radio[0] to point to the radio button. You can assign an ID to it and use getElementById method to use it in Javascript. Another easy way is to pass the object to the function. Please refer to the sample code below:

<script>
    function test(radioObj) {
        if(radioObj.value == "0")
            alert("Hello1");
        else if (radioObj.value == "1")
            alert("Hello2");
    }
</script>

<input type="radio" name="test" onclick="test(this)" value="0">
<input type="radio" name="test" onclick="test(this)" value="1">