JavaScript：在Chrome中使用textarea.setSelectionRange后滚动到选择 [英] JavaScript: Scroll to selection after using textarea.setSelectionRange in Chrome

问题描述

javascript函数使用.setSelectionRange（）选择textarea中的某个单词。在Firefox中，textarea自动向下滚动以显示选定的文本。在Chrome（v14）中，它没有。有没有办法让Chrome浏览器滚动到新选定的文本？ jQuery解决方案欢迎。

解决方案

以下是一个简单高效的解决方案，纯js：

  //首先，你忽略任何不好的英语，因为我是法语的，并且有一个有趣的晚上
 //得到textarea 
 var textArea = document.getElementById（'myTextArea'）; 
 
 //定义您的选择
 var selectionStart = 50; 
 var selectionEnd = 60; 
 textArea.setSelectionRange（selectionStart，selectionEnd）; 
 
 //现在让我们做一些数学
 //我们需要一行中的字符数
 var charsPerRow = textArea.cols; 
 
 //我们需要知道我们的选择在哪一行开始
 var selectionRow =（selectionStart  - （selectionStart％charsPerRow））/ charsPerRow; 
 
 //我们需要滚动到这一行，但滚动以像素为单位，
 //所以我们需要知道一行的高度，以像素为单位
 var lineHeight = textArea.clientHeight / textArea.rows; 
 
 //滚动！ 
 textArea.scrollTop = lineHeight * selectionRow; 
  

把它放在一个函数中，用它扩展javascript的Element对象的原型， 。

随意问你是否需要任何帮助。

A javascript function selects a certain word in a textarea using .setSelectionRange(). In Firefox, the textarea automatically scrolls down to show the selected text. In Chrome (v14), it does not. Is there a way to get Chrome to scroll the textarea down to the newly selected text? jQuery solutions welcome.

解决方案

Here is a simple and efficient solution, pure js :

//first of all, you ignore any bad english, as i'm french and had a funny evening
//get the textarea
var textArea = document.getElementById('myTextArea');

//define your selection
var selectionStart = 50;
var selectionEnd = 60;
textArea.setSelectionRange( selectionStart, selectionEnd);

// now lets do some math
// we need the number of chars in a row
var charsPerRow = textArea.cols;

// we need to know at which row our selection starts
var selectionRow = (selectionStart - (selectionStart % charsPerRow)) / charsPerRow;

// we need to scroll to this row but scrolls are in pixels,
// so we need to know a row's height, in pixels
var lineHeight = textArea.clientHeight / textArea.rows;

// scroll !!
textArea.scrollTop = lineHeight * selectionRow;

Put this in a function, extend the prototype of javascript's Element object with it, and you're good.

Feel free to ask if you need any further help.

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