I need to check the checked property of a checkbox and perform an action based on the checked property using jQuery.
For example, if the age checkbox is
Though you have proposed a JavaScript solution for your problem (displaying a textbox when a checkbox is checked), this problem could be solved just by css. With this approach, your form works for users who have disabled JavaScript.
Assuming that you have the following HTML:
You can use the following CSS to achieve the desired functionality:
#show_textbox:not(:checked) + input[type=text] {display:none;}
For other scenarios, you may think of appropriate CSS selectors.
Here is a Fiddle to demonstrate this approach.