Placement of checkbox label

I want the check box label to appear before the checkbox. The issue is, I can't make use of the attribute for="checkbox id" in label, unless the label comes after the check box. I strictly need to use the combination of check box and label, i.e. I can't use nested label or a check box with < p> or < span> before it. Can someone aid in this. Thank you.

<input type="checkbox" id="chk1" />
<label for="chk1">I agree</label>