Check a radio button with javascript
Today, in the year 2016, it is safe to use document.querySelector
without knowing the ID (especially if you have more than 2 radio buttons):
document.querySelector("input[name=main-categories]:checked").value
If you want to set the "1234" button, you need to use its "id":
document.getElementById("_1234").checked = true;
When you're using the browser API ("getElementById"), you don't use selector syntax; you just pass the actual "id" value you're looking for. You use selector syntax with jQuery or .querySelector()
and .querySelectorAll()
.
Do not mix CSS/JQuery syntax (#
for identifier) with native JS.
Native JS solution:
document.getElementById("_1234").checked = true;
JQuery solution:
$("#_1234").prop("checked", true);