how to make checkbox as radio button code example

Example 1: checkbox as radio button

input[type=checkbox]:not(old) + label,
input[type=radio   ]:not(old) + label{
  display      : inline-block;
  margin-left  : -2em;
  line-height  : 4em;
}

Example 2: checkboxes and radio buttons

- We locate, and we click on them. 
isSelected() isSelected()--> true,  else --> false 
This method checks if the checkbox/radiobutton is selected or not selected. 
isEnabled() isEnabled -> true,  else --> false
This method checks if the checkbox/radiobutton is enabled to be clicked.      
isDispalyed()  isDispalyed()-> true, else --> false
verify the presence of a web element within the web page.                          

    syntax: driver.findElement(LOCATOR).isSelected();   
    syntax: driver.findElement(LOCATOR).isEnabled();
StaleElementReferenceException: 
A stale element reference exception is thrown in one of two cases
1- The element has been deleted entirely.
2- The element is no longer attached to the DOM.
    WebElement checkbox = driver.findElement(LOCATOR); 
    checkbox.click; driver.navigate().refresh(); 
    checkbox = driver.findElement(LOCATOR);
    checkbox.click();  <--stale element reference exception will be thrown