<!DOCTYPE html> <html> <head> <style> label {color: red} input[checked]:checked:default ~ label {color: green} </style> </head> <body onload='var form = document.getElementById("form"); var input2 = document.createElement("input"); input2.setAttribute("type", "checkbox"); input2.setAttribute("id", "two"); input2.setAttribute("checked", "true"); form.insertBefore(input2, form.firstChild); var label2 = document.createElement("label"); label2.setAttribute("for", "two"); var text2 = document.createTextNode("Should be no red"); label2.appendChild(text2); form.insertBefore(label2, document.getElementById("one"));'> <form id="form"> <input type="checkbox" name="group1" id="one" value="1"/> <label for="one">Should be no red</label> </form> </body> </html>