如何在输入中获取文本插入符号的索引？
在 HTML 输入中获取插入符号位置？
IT技术
javascript
html
caret
2021-02-01 02:35:02
5个回答
->选择开始
<!doctype html>
<html>
<head>
<meta charset = "utf-8">
<script type = "text/javascript">
window.addEventListener ("load", function () {
var input = document.getElementsByTagName ("input");
input[0].addEventListener ("keydown", function () {
alert ("Caret position: " + this.selectionStart);
// You can also set the caret: this.selectionStart = 2;
});
});
</script>
<title>Test</title>
</head>
<body>
<input type = "text">
</body>
</html>
以下内容将为您提供选择的开始和结束作为字符索引。它适用于文本输入和文本区域，并且由于 IE 对换行符的奇怪处理而稍微复杂一些。
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 textBox = document.getElementById("textBoxId");
textBox.focus();
alert( getInputSelection(textBox).start );
现在有一个很好的 jQuery 插件：Caret plugin
然后你可以打电话 $("#myTextBox").caret();
我们曾在一个旧的 javascript 应用程序中使用过这样的东西，但我已经有几年没有测试过它了：
function getCaretPos(input) {
// Internet Explorer Caret Position (TextArea)
if (document.selection && document.selection.createRange) {
var range = document.selection.createRange();
var bookmark = range.getBookmark();
var caret_pos = bookmark.charCodeAt(2) - 2;
} else {
// Firefox Caret Position (TextArea)
if (input.setSelectionRange)
var caret_pos = input.selectionStart;
}
return caret_pos;
}
在文本框中获取光标点的工作示例：
function textbox()
{
var ctl = document.getElementById('Javascript_example');
var startPos = ctl.selectionStart;
var endPos = ctl.selectionEnd;
alert(startPos + ", " + endPos);
}
其它你可能感兴趣的问题