How can I write this as a JavaScript function?

Question

I have the following code snippet embedded into some of my divs so when those divs get clicked a certain radio button gets checked.

onclick="document.g1.city[0].checked=true;"

However I would like to convert the above call to a function call like below:

onclick="checkRadioButton(city[0]);"

And the function will be something like this

function checkRadioButton(input){
    document.g1.input.checked=true;
}

Is there a way I can accomplish this?

Answer 1

onclick="checkRadioButton(document.g1.city[0]);"

checkRadioButton(var input){
    input.checked=true;
}

You can also reduce the need for supplying document.g1.city[0] if, for example, every DIV that you mark thusly has an attribute "radioID", and the value of the attribute must match the ID given to the radio button:

onclick="checkRadioButton(this);"

checkRadioButton(var div){
    document.getElementById(div.radioID).checked=true;
}

Answer 2

You can write any Javascript code inside the onclick attribute. Remember that city[0] is not defined anywhere. To access it, you must specify the full document.g1.city[0]. So the onclick becomes:

onclick="checkRadioButton(document.g1.city[0]);"

Inside your function, you are already receiving the element, and don't have to retrieve it from the document again. You could directly set it's checked property:

function checkRadioButton(input) {
   input.checked = true;
}