您可以使用jquery来更改nav-index和nav-up。

$('a#a1').attr('nav-index', '2'); //If you want to change it to 2.
$('a#a1').attr('nav-up', '#5'); //If you want to change it to #5.

document.getElementById('a1').style.navIndex = newIndex;
document.getElementById('a1').style.navUp = newValue;

请注意，根据this和this，nav-index和nav-up仅受Opera支持。

[2023年]查看此Stackblitz snippet
就像这样：

var a1 = document.getElementById('a1');
a1.style['nav-index'] = /* somevalue */;
a1.style['nav-up']    = /* somevalue */;
// or (style properties with hypens must be converted
// to a camel case representation for use in 'dot notation')
a1.style.navIndex = /* somevalue */;
a1.style.navUp    = /* somevalue */;
// and to retrieve the original values:
a1.style['nav-index'] = '';
a1.style['nav-up']    = '';

此外，建议将内联样式转移到css文件中的类中。

.a1nav {
 position:absolute;
 top:0;
 left:0;
 nav-index:1;
 nav-down:#b1;
 nav-right:#a3;
 nav-left:#a1;
 nav-up:#a1;
}

创建一个新的css并调用他们使用像这样

function changeClass (elementID, newClass) {
    var element = document.getElementById(elementID);

    element.setAttribute("class", newClass); //For Most Browsers
    element.setAttribute("className", newClass); //For IE; harmless to other browsers.
}