Checkbox to change textdecoration input field

With javascript, i want my checkbox to change the text decoration of an input text field. So when it's checked, the text in the input text field turns bold.

Remember i'm learning so i'm not a pro as you guys ;)

I thought something like this;

var checkbox = create("input");
    checkbox.type = "checkbox";
    checkbox.id = "checkboxId" + counter;
    div.appendChild(checkbox);
    checkbox.onClick="boldChange(this)"

var input = create("input");
    input.type = "input";
    input.id = "inputId" + counter;
    div.appendChild(input);



function boldChange()
var boldgroup = document.getElementsByName(el.name);
for (var b=0; boldgroup[b]; ++b开发者_运维知识库)
inputId.style.textDecoration = boldgroup[b].checked ? 'bold' : 'none';
}

How can i make this work? Thank you so much in advance

---

Here is a working JSFiddle example based on your code above: Link to example

Code snippet: (place below </body> so that all of DOM is loaded)

<script>
    var div = document.getElementById('div'),
    counter = 0;

    var checkbox = document.createElement("input");
    checkbox.type = "checkbox";
    checkbox.id = "checkboxId" + counter;
    div.appendChild(checkbox);
    checkbox.onclick = boldChange;
    counter++;

    var input = document.createElement("input");
    input.type = "text";
    input.id = "inputId" + counter;
    div.appendChild(input);



    function boldChange() {
        input.style.fontWeight = (checkbox.checked)?'bold':'normal';
    }
</script>