Replacing cloneNode() in jquery

Replacing cloneNode() in jquery

I am not very experienced in jquery. I have one function written in java
script, wanted to replace with jquery language. But some errors are keep
coming up while doing that. the function is

function moreFields() {
counter++; var newFields =
document.getElementById('readroot').cloneNode(true);
newFields.id = '';
newFields.style.display = 'block';
var newField = newFields.childNodes;
for (var i=0;i<newField.length;i++)
{
var theName = newField[i].name
if (theName)
newField[i].name = theName + counter;
}
var insertHere = document.getElementById('writeroot');
insertHere.parentNode.insertBefore(newFields,insertHere);
}
If anyone can help me out on this, I will be very much obliged.