Dashboard Widgets只是运行在WebKit技术上， for Safari也应该在Dashcode中有效。以下任一应该工作：

Dashboard Widgets just run on WebKit technologies, so code valid for Safari should also be valid in Dashcode. Either of the following should work:

checkbox.checked = true;
checkbox.setAttribute("checked", "true");

它们不工作的事实表明在代码的其他地方有一个问题。我会检查行

The fact that they are not working indicates there is a problem elsewhere in your code. I would check the line

var checkbox = document.getElementById("checkbox");     

正确地为复选框分配一个元素 。此外，检查您的checkbox元素的id是否有效且正确（不是重复，没有拼写错误等）。

Correctly assigns an element to the checkbox variable. Also, check the id of your "checkbox" element is valid and correct (not a duplicate, doesn't have a typo, etc).