用纯Js在每个li上应用函数

时间:2012-08-12 03:42:36

标签: javascript loops

我已经完成了一个使用语音api读出元素内容的函数,我有一个像这样的新闻列表

<ul id="news">
    <li>
How Instagram Is Winning Gold at the 2012 Olympics [INFOGRAPHIC]
   </li><li>
      Flickr Photo of Insect Identified As Never-Before-Seen Species [VIDEO]
   </li><li>
      The Upside to the End of the Olympics [COMIC]
   </li><li>
      40 Digital Media Resources You May Have Missed
   </li><li>
      19 Resources to Improve Your Photo and Video Skills
   </li><li>
      Top 10 Twitter Pics of the Week
   </li><li>
      Can Employees Be Trusted to Work From Home? [INFOGRAPHIC]
   </li><li>
      Capture Ghosts at Foursquare Spots With ‘Ghostbusters’ iOS Game
   </li><li>
      Dog Is Terrified of Low-Fat Lamb Jerky [VIDEO]
   </li><li>
      5 Tips to Take Food Photos Good Enough to Eat
   </li><li>
      The 10 Most Stunning Images of Mars in History
   </li><li>
      The Many Looks of Spiderman Over the Past 50 Years [INFOGRAPHIC]
   </li><li>
      Top Ten GIFs of the Week
   </li><li>
      Romney and Obama Both Called Their Veeps the ‘Next President’ [VIDEO]
   </li><li>
      Paul Ryan Visited Facebook, Met Zuckerberg [PICS]
   </li><li>
      Romney’s Logo Looks Like Toothpaste [PICS]
   </li><li>
      Paul Ryan, Romney’s VP Pick, Has Sizable Online Presence
   </li><li>
      Get Back in Kitchen With This Specialized Recipe Site
   </li>

</ul>

现在正在使用此功能读出文本。

function speak() {
    //speechapi.speak(document.getElementById('start').innerHTML,"male");
    speechapi.speak(document.getElementById('start').innerHTML,"male");

}

如何让它在每个li之间以较小的间隔读取?我不想使用jquery或类似。 但我无法做到。

3 个答案:

答案 0 :(得分:1)

怎么样

function speak() {
    var i = 0,
    li = document.getElementById('news').getElementsByTagName('li'),
    interval = setInterval(function(){
        if (i < li.lenght){
            speechapi.speak(li[i].innerHTML,"male");
            i++;
        }
        else{
            clearInterval(interval);
        }
    }, 5000);
}

https://developer.mozilla.org/en-US/docs/DOM/document.getElementsByTagName

https://developer.mozilla.org/en-US/docs/DOM/document.getElementById

https://developer.mozilla.org/en-US/docs/window.setInterval

https://developer.mozilla.org/en/DOM/window.clearInterval

答案 1 :(得分:1)

这是一种方法,每行之间延迟2秒:

var news = document.getElementById('news').getElementsByTagName('li');

var newsItem = 0;
var speechInterval = setInterval(function(){
    speechapi.speak(news[newsItem].innerHTML, "male");
    if (++newsItem === news.length){
        window.clearInterval(speechInterval);
    }
}​, 2000);

DEMO, inserting text in a <p> tag instead of speaking it

答案 2 :(得分:1)

以下是我对这个问题的看法:

function speak() {
    var li = document.getElementById ('news').getElementsByTagName ('li')
      , i = 0;

    li = [].slice.call (li, 0);

    (function speakItem() {
      speechapi.speak(li[i++].innerHTML, "male");
      i < li.length && window.setTimeout (speakItem, 1000);
    }
}

[].slice.call (li, 0)将li元素的实时列表转换为简单的JS数组,从而提高处理效率。

读取每个项目,然后,如果有更多项目,则在说出下一个项目之前开始1秒间隔。这允许长项和短项目之间具有恒定的间隔。