a/19540988/1636522

HTML

<input id="a"name="a" type="checkbox" value="1" checked="checked" >A</input>
<input id="a"name="a" type="checkbox" value="2" checked="checked" >B</input>
<input id="a"name="a" type="checkbox" value="3" checked="checked" >C</input><br/>
<button onclick="send_query(document.getElementsByTagName('input'))">Values</button>
<span>: "<span></span>"</span>

CSS

*{font-family:Consolas}

JavaScript

var log;

function send_query(check) {

		
    
    var values = [];
    for (i = 0; i < check.length; i++) {
        if (check[i].checked == true) {
            values.push(check[i].value);
        }
    }
    
}

onload = function () {
    log = document.getElementsByTagName('span')[1];
    send_query(document.getElementsByTagName('input'));
};