jQuery：通过 .attr() 添加两个属性；方法

应该有效:

.attr({
    target:"nw", 
    title:"Opens in a new window",
    "data-value":"internal link" // attributes which contain dash(-) should be covered in quotes.
});

Note:

" When setting multiple attributes, the quotes around attribute names are optional.

100: When setting the 'class' attribute, you must always use quotes!

根据jQuery文档(2016年9月)中的.attr:

试图更改通过文档创建的输入或按钮元素的type属性.createElement()将在Internet Explorer 8或更早版本上引发异常.

Edit:
For future reference... To get a single attribute you would use

var strAttribute = $(".something").attr("title");

To set a single attribute you would use

$(".something").attr("title","Test");

到set multiple个属性，您需要将所有内容包装在{…}

$(".something").attr( { title:"Test", alt:"Test2" } );

编辑-如果您试图从复选框中获取/设置"Checked"属性.

您需要使用prop() as of jQuery 1.6+

the .prop() method provides a way to explicitly retrieve property values, while .attr() retrieves attributes.

...the most important concept to remember about the checked attribute is that it does not correspond to the checked property. The attribute actually corresponds to the defaultChecked property and should be used only to set the initial value of the checkbox. The checked attribute value does not change with the state of the checkbox, while the checked property does

因此，对于复选框的get the checked status，您应该使用:

$('#checkbox1').prop('checked'); // Returns true/false

或设置为set the checkbox as checked or unchecked，您应该使用:

$('#checkbox1').prop('checked', true); // To check it
$('#checkbox1').prop('checked', false); // To uncheck it