原始的js程式碼和jquery對比體會_基礎知識

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:

程式碼如下:

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

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

在我們自己處理的時候，甚至是這麼簡單的任務在不使用jquery的時候都會變得複雜。用原始的js，我們可以使用下面的程式碼片段來加入highlighted類別：

Despite its length, this solution does not handle many of the situations that jQuery takes care of for us in Listing 1.2, wings 1.2, wing :
• Properly respecting other window.onloadevent handlers
• Acting as soon as the DOM is ready
• Optimizing element retrieval and other tasks with modern DOM methods 1、合適的處理其他的window.load事件
2、在DOM結構準備好的時候開始行動。
3、使用現代的DOM方法來最佳化元素查找和其他任務。

We can see that our jQuery-driven code is easier to write, simpler to read, and faster to execute than its plain JavaScript equivalent.

我們可以清晰的看到我們的使用query的程式碼比原生js程式碼寫起來更容易，讀起來更簡單，運行起來更快。