Do not mix CSS/JQuery syntax (# for identifier) with native JS. Native JS solution: palmcolors.commentById("_").checked = true;. JQuery solution.
Value, Description. true|false, Specifies whether a radio button should be checked or not. true - The radio button is checked; false - Default. The radio button is.
I'm used to write my own statitc html code into the palmcolors.com file of palmcolors.com sketch. So I use the select() function of the DOM library to access html.
Checking radio buttons on a form is a little trickier. You have to loop through each button, testing for a value of checked, which means it was selected. Only one.