我有一个自定义文本区域。在这个例子中,它随机地使字母变成红色或绿色。
var mydiv = document.getElementById('mydiv'),
myta = document.getElementById('myta');
function updateDiv() {
var fc;
while (fc = mydiv.firstChild) mydiv.removeChild(fc);
for (var i = 0; i < myta.value.length; i++) {
var span = document.createElement('span');
span.className = Math.random() < 0.5 ? 'green' : 'red';
span.appendChild(document.createTextNode(myta.value[i]));
mydiv.appendChild(span);
}
};
myta.addEventListener('input', updateDiv);
body { position: relative }
div, textarea {
-webkit-text-size-adjust: none;
width: 100%;
white-space: pre-wrap;
word-wrap: break-word;
overflow-wrap: break-word;
font: 1rem sans-serif;
padding: 2px;
margin: 0;
border-radius: 0;
border: 1px solid #000;
resize: none;
}
textarea {
position: absolute;
top: 0;
color: transparent;
background: transparent;
}
.red { color: #f00 }
.green { color: #0f0 }
<div id="mydiv"></div>
<textarea id="myta" autofocus=""></textarea>
上面有一个带有文本区域的输出 div。所以textarea不会遮住它下面的任何彩色东西,它的颜色和背景都设置为透明的。此处一切正常,除了插入符号(用户代理提供的闪烁光标)是透明的。
有没有办法在不使文本区域的文本可见的情况下显示插入符号?
如果我改为在文本区域上方创建 div 并为其提供 pointer-events: none
,则文本区域在下方仍然可见。这种安排也使平滑滚动变得困难,所以它对我不起作用。
最佳答案
只需插入您自己的插入符!
function blink() {
document.getElementById('caret').hidden ^= 1;
blinkTimeout = setTimeout(blink, 500);
}
var mydiv = document.getElementById('mydiv'),
myta = document.getElementById('myta'),
blinkTimeout = setTimeout(blink, 500),
lastSelectionStart = 0,
lastSelectionEnd = 0,
whichSelection = true;
function updateDiv() {
var fc;
while (fc = mydiv.firstChild) mydiv.removeChild(fc);
if (myta.selectionStart != lastSelectionStart) {
lastSelectionStart = myta.selectionStart;
whichSelection = false;
}
if (myta.selectionEnd != lastSelectionEnd) {
lastSelectionEnd = myta.selectionEnd;
whichSelection = true;
}
var cursorPos = whichSelection ? myta.selectionEnd : myta.selectionStart;
for (var i = 0; i < myta.value.length; i++) {
if (i == cursorPos) {
var caret = document.createElement('span');
caret.id = 'caret';
caret.appendChild(document.createTextNode('\xA0'));
mydiv.appendChild(caret);
clearTimeout(blinkTimeout);
blinkTimeout = setTimeout(blink, 500);
}
var span = document.createElement('span');
span.className = Math.random() < 0.5 ? 'green' : 'red';
span.appendChild(document.createTextNode(myta.value[i]));
mydiv.appendChild(span);
}
if (myta.value.length == cursorPos) {
var caret = document.createElement('span');
caret.id = 'caret';
caret.appendChild(document.createTextNode('\xA0'));
mydiv.appendChild(caret);
clearTimeout(blinkTimeout);
blinkTimeout = setTimeout(blink, 500);
}
};
myta.addEventListener('input', updateDiv);
myta.addEventListener('focus', updateDiv);
myta.addEventListener('mousedown', function() {
setTimeout(updateDiv, 0);
});
myta.addEventListener('keydown', function() {
setTimeout(updateDiv, 0);
});
myta.addEventListener('blur', function() {
document.getElementById('caret').hidden = true;
clearTimeout(blinkTimeout);
});
body { position: relative }
div, textarea {
-webkit-text-size-adjust: none;
width: 100%;
white-space: pre-wrap;
word-wrap: break-word;
overflow-wrap: break-word;
font: 1rem sans-serif;
padding: 2px;
margin: 0;
border-radius: 0;
border: 1px solid #000;
resize: none;
}
textarea {
position: absolute;
top: 0;
color: transparent;
background: transparent;
}
.red { color: #f00 }
.green { color: #0f0 }
#caret {
display: inline-block;
position: absolute;
width: 1px;
background: #000;
}
#caret[hidden] { display: none }
<div id="mydiv"><span id="caret"> </span></div>
<textarea id="myta" autofocus=""></textarea>
我这里有一个<span>
#caret
通过使用 JS 切换其隐藏属性,插入到每 500 毫秒闪烁一次的 div 中。要复制浏览器行为,我必须检测它是否是 selectionStart
或 selectionEnd
插入符实际所在的位置,并在输入文本时使其保持固定状态。
当跨度不是固定长度或嵌套时,这有点难以实现,但它比使用更复杂的荧光笔摆弄 contentEditable 更容易。此函数会将插入符插入正确的位置:
function insertNodeAtPosition(node, refNode, pos) {
if (typeof(refNode.nodeValue) == 'string') refNode.parentNode.insertBefore(node, refNode.splitText(pos));
else {
for (var i = 0; i < refNode.childNodes.length; i++) {
var chNode = refNode.childNodes[i];
if (chNode.textContent.length <= pos && i != refNode.childNodes.length - 1) pos -= chNode.textContent.length;
else return insertNodeAtPosition(node, chNode, pos);
}
}
}
用法(其中 i
是插入它的位置):
var caret = document.createElement('span');
caret.id = 'caret';
caret.appendChild(document.createTextNode('\xA0'));
insertNodeAtPosition(caret, mydiv, i);
clearTimeout(blinkTimeout);
blinkTimeout = setTimeout(blink, 500);
关于javascript - 在自定义文本区域中显示插入符号而不显示其文本,我们在Stack Overflow上找到一个类似的问题: https://stackoverflow.com/questions/30971773/