是否可以通过编程方式检测< input type = text>中的插入符号位置.元素? [英] Is it possible to programmatically detect the caret position within a <input type=text> element?
问题描述
假设一个常规的< input type = text>
文本框中包含数据.
Assuming a regular <input type=text>
text-box with data in it.
是否可以(通过JavaScript)检测文本向导在该文本框中的位置?
Is it possible to detect (via JavaScript) the position of the text-coursor inside that text-box?
我能够检测到ARROW LEFT或ARROW RIGHT按下事件-但是如何检测光标位置?
I am able to detect an ARROW LEFT or ARROW RIGHT keydown event - but how to detect the cursor location?
为什么我需要这个:
Why I need this:
我在这里有一个动态文本框: http://vidasp.net/tinydemos/dynamic-textbox.html
效果很好,但是我要修复两种情况:
I have a dynamic text-box here: http://vidasp.net/tinydemos/dynamic-textbox.html
It works great, however there are two scenarios that I would like to fix:
- 当光标位于文本框的开头并且用户按BACKSPACE时
- 当光标位于文本框的末尾并且用户按下DELETE时
(在两种情况下,文本框都必须包含数据才能使效果可见.)
(In both cases, the text-box must contain data for the effect to be observable.)
推荐答案
我已经做了很多工作.以下内容适用于所有主要浏览器(包括IE 6),适用于文本< input>
和< textarea>
前导和尾随空格(这是许多解决方案(包括a-tools)掉落的地方).此问题中的这段代码有一些背景:IE的document.selection.createRange不包含开头或结尾的空白行
I've done quite a lot of work on this. The following works in all major browsers (including IE 6) for text <input>
s and <textarea>
s and will work in all situations, including when there are leading and trailing spaces (which is where many solutions, including a-tools, fall down). There's some background to this code in this question: IE's document.selection.createRange doesn't include leading or trailing blank lines
作为我编写的jQuery input/textarea选择插件的一部分,您还可以获得以下内容:
You can also get the following as part of a jQuery input/textarea selection plug-in I've written that is as yet undocumented: http://code.google.com/p/rangyinputs/
function getInputSelection(el) {
var start = 0, end = 0, normalizedValue, range,
textInputRange, len, endRange;
if (typeof el.selectionStart == "number" && typeof el.selectionEnd == "number") {
start = el.selectionStart;
end = el.selectionEnd;
} else {
range = document.selection.createRange();
if (range && range.parentElement() == el) {
len = el.value.length;
normalizedValue = el.value.replace(/\r\n/g, "\n");
// Create a working TextRange that lives only in the input
textInputRange = el.createTextRange();
textInputRange.moveToBookmark(range.getBookmark());
// Check if the start and end of the selection are at the very end
// of the input, since moveStart/moveEnd doesn't return what we want
// in those cases
endRange = el.createTextRange();
endRange.collapse(false);
if (textInputRange.compareEndPoints("StartToEnd", endRange) > -1) {
start = end = len;
} else {
start = -textInputRange.moveStart("character", -len);
start += normalizedValue.slice(0, start).split("\n").length - 1;
if (textInputRange.compareEndPoints("EndToEnd", endRange) > -1) {
end = len;
} else {
end = -textInputRange.moveEnd("character", -len);
end += normalizedValue.slice(0, end).split("\n").length - 1;
}
}
}
}
return {
start: start,
end: end
};
}
var el = document.getElementById("your_input");
var sel = getInputSelection(el);
alert(sel.start + ", " + sel.end);
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