如何将选中的复选框值设置为脚本中的变量

<input type="checkbox" id="checkbox1" value="value1"> Option 1
<input type="checkbox" id="checkbox2" value="value2"> Option 2
<input type="checkbox" id="checkbox3" value="value3"> Option 3

var checkbox1 = document.getElementById("checkbox1");
var checkbox2 = document.getElementById("checkbox2");
var checkbox3 = document.getElementById("checkbox3");

var value1 = checkbox1.checked ? checkbox1.value : "";
var value2 = checkbox2.checked ? checkbox2.value : "";
var value3 = checkbox3.checked ? checkbox3.value : "";