The <asp:radiobutton> and <asp:radiobuttonlist> Controls
In HTML, radio buttons are used when we need to make multiple sets of choices available, but we want the user to select only one of them. If they click on a second selection after making a first, the first selection is removed and replaced by the second. Radio buttons are implemented in HTML using the <input> tag, and setting the type attribute to radio. Every radio button on the page needs to have its own <input type="radio"> tag. Each radio button within a particular group must have the same name attribute.
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