调用Java脚本函数的所有目标元素

Question

我发现了一个javascript function，我想应用到所有目标元素，在我的情况下，从网页中的所有文本区域，但是当我为了我改变从document.getElementById('text');选择为document.querySelectorAll('textarea');或document.getElementsByTagName('textarea')目标所有元素不工作，我不明白为什么，我试图把text变量在for，但仍无法正常工作，如果有人可以帮我一点点这个虚拟的问题：|

Answer 1

你在正确的轨道与一个循环，你只是没有走得足够远（见注释）：

function init() { 
    var list, i, text; 

    // Get the list 
    list = document.getElementsByTagName('textarea'); 

    // Loop through it 
    for (i = 0; i < list.length; ++i) { 
     // Get this entry 
     text = list[i]; 

     // Do things with it 
     observe(text, 'change', resize); 
     observe(text, 'cut',  delayedResize); 
     observe(text, 'paste', delayedResize); 
     observe(text, 'drop', delayedResize); 
     observe(text, 'keydown', delayedResize); 

     // Initial `resize` call -- I'm using `.call` in order to 
     // set `this` to the element during the call, like an event 
     // does 
     resize.call(text); 

     // You'll have to choose *one* of them to focus; I chose the first 
     if (i == 0) { 
      text.focus(); 
      text.select(); 
     } 
    } 
    function resize() { 
     // Note that I'm using `this` here, not `text` or `list` 
     // `this` will refer to the element the event is occurring on 
     this.style.height = 'auto'; 
     this.style.height = this.scrollHeight+'px'; 
    } 

    // 0-timeout to get the already changed text 
    function delayedResize() { 
     // Again note the use of `this`, also `.bind`. 
     // `Function#bind` creates a function that, when called, 
     // calls the original with a specific `this` value 
     window.setTimeout(resize.bind(this), 0); 
    } 
}