Check a radio button with javascript

For some reason, I can't seem to figure this out.

I have some radio buttons in my html which toggles categories:

<input type="radio" name="main-categories" id="_1234" value="1234" /> // All
<input type="radio" name="main-categories" id="_2345" value="2345" /> // Certain category
<input type="radio" name="main-categories" id="_3456" value="3456" /> // Certain category
<input type="radio" name="main-categories" id="_4567" value="4567" /> // Certain category

The user can select whichever he/she wants, but when an certain event triggers, I want to set 1234 to be set checked radio button, because this is the default checked radio button.

I have tried versions of this (with and without jQuery):

document.getElementById('#_1234').checked = true;

But it doesn't seem to update. I need it to visibly update so the user can see it. Can anybody help?

EDIT: I'm just tired and overlooked the #, thanks for pointing it out, that and $.prop().

Solution 1:

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);

Solution 2:

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().

Solution 3:

Today, in the year 2016, it is save 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