show blinking cursor when field is visible

I have a text field which at times is hidden. But, when I select it to be visible from the popMenu list it becomes visible (no problem there) but the cursor within the text field isn't visible, I have to click inside the text field to see it. What I would like to happen is to have the cursor visible when I choose to show that text field and not have to click inside the field. Is there a javascript that will enable the cursor to be visible as well as the field itself?