Even a task as simple as this can be complicated without jQuery at our disposal. In plain JavaScript, we could add the highlightedclass as shown in the following code snippet:

復制代碼 代碼如下:

window.onload = function() {
var divs = document.getElementsByTagName('div');
for (var i = 0; i < divs.length; i++) {
if (hasClass(divs[i], 'poem-stanza') && !hasClass(divs[i], 'highlight')) {
divs[i].className += ' highlight';

}
}
function hasClass( elem, cls ) {
var reClass = new RegExp(' ' + cls + ' ');
return reClass.test(' ' + elem.className + ' ');
}
};