我想要一个文本区域,可以处理按Tab键的情况。
在默认情况下,如果您按Tab键,则焦点将离开文本区域。但是,当用户想要在文本区域中输入tab键时会怎样呢?
我可以捕获此事件并将焦点返回到textarea并将标签添加到当前光标位置吗?
我想要一个文本区域,可以处理按Tab键的情况。
在默认情况下,如果您按Tab键,则焦点将离开文本区域。但是,当用户想要在文本区域中输入tab键时会怎样呢?
我可以捕获此事件并将焦点返回到textarea并将标签添加到当前光标位置吗?
indent-textarea
Answers:
您可以:http : //jsfiddle.net/sdDVf/8/。
$("textarea").keydown(function(e) {
if(e.keyCode === 9) { // tab was pressed
// get caret position/selection
var start = this.selectionStart;
var end = this.selectionEnd;
var $this = $(this);
var value = $this.val();
// set textarea value to: text before caret + tab + text after caret
$this.val(value.substring(0, start)
+ "\t"
+ value.substring(end));
// put caret at right position again (add one for the tab)
this.selectionStart = this.selectionEnd = start + 1;
// prevent the focus lose
e.preventDefault();
}
});
return false
似乎包括preventDefault
:stackoverflow.com/questions/1357118/…。
selectionStart
/ selectionEnd
。您必须创建文本范围,但恐怕我还是不明白它的工作原理……
+ value.substring(start, end));
-否则在选择文本时使用制表键会擦除文本。
这是pimvdb答案的修改版本,不需要JQuery:
document.querySelector("textarea").addEventListener('keydown',function(e) {
if(e.keyCode === 9) { // tab was pressed
// get caret position/selection
var start = this.selectionStart;
var end = this.selectionEnd;
var target = e.target;
var value = target.value;
// set textarea value to: text before caret + tab + text after caret
target.value = value.substring(0, start)
+ "\t"
+ value.substring(end);
// put caret at right position again (add one for the tab)
this.selectionStart = this.selectionEnd = start + 1;
// prevent the focus lose
e.preventDefault();
}
},false);
我在Firefox 21.0和Chrome 27中对其进行了测试。不知道它是否可以在其他地方使用。
document.querySelectorAll("textarea")
2)循环通过数组将事件侦听器附加到每个元素。然后它应该起作用
天哪,以前的所有答案都未能提供通常不错的(例如,对于程序员)选项卡控件。
也就是说,TAB选择行将使这些行SHIFTTAB缩进,并将它们取消缩进。
_edited(2016年11月):将keyCode替换为charCode || 每个KeyboardEvent.charCode的keyCode -Web API | MDN
(function($) {
$.fn.enableSmartTab = function() {
var $this;
$this = $(this);
$this.keydown(function(e) {
var after, before, end, lastNewLine, changeLength, re, replace, selection, start, val;
if ((e.charCode === 9 || e.keyCode === 9) && !e.altKey && !e.ctrlKey && !e.metaKey) {
e.preventDefault();
start = this.selectionStart;
end = this.selectionEnd;
val = $this.val();
before = val.substring(0, start);
after = val.substring(end);
replace = true;
if (start !== end) {
selection = val.substring(start, end);
if (~selection.indexOf('\n')) {
replace = false;
changeLength = 0;
lastNewLine = before.lastIndexOf('\n');
if (!~lastNewLine) {
selection = before + selection;
changeLength = before.length;
before = '';
} else {
selection = before.substring(lastNewLine) + selection;
changeLength = before.length - lastNewLine;
before = before.substring(0, lastNewLine);
}
if (e.shiftKey) {
re = /(\n|^)(\t|[ ]{1,8})/g;
if (selection.match(re)) {
start--;
changeLength--;
}
selection = selection.replace(re, '$1');
} else {
selection = selection.replace(/(\n|^)/g, '$1\t');
start++;
changeLength++;
}
$this.val(before + selection + after);
this.selectionStart = start;
this.selectionEnd = start + selection.length - changeLength;
}
}
if (replace && !e.shiftKey) {
$this.val(before + '\t' + after);
this.selectionStart = this.selectionEnd = start + 1;
}
}
});
};
})(jQuery);
$(function() {
$("textarea").enableSmartTab();
})
<script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.1/jquery.min.js"></script>
<textarea rows="10" cols="80">
/* Just some code to edit with our new superTab */
(function($) {
$.fn.enableSmartTab = function() {
$this = $(this);
$this.keydown(function(e) {
if ((e.charCode === 9 || e.keyCode === 9) && !e.metaKey && !e.ctrlKey && !e.altKey) {
e.preventDefault();
}
}
}
}
</textarea>
event.key
(IIRC)在各浏览器之间也不是一致的,键在不同浏览器中可能称为不同的事物,而Safari根本不支持该属性。这是人们使用jQuery的另一个原因,尽管它经常被人们遗忘,但它是为了保证跨浏览器的兼容性。我不是在批评您的努力,我认为您做了出色的工作,但是必须跨浏览器工作
$.fn.val
。处理程序本身已经使用了本机事件属性。
在Vanilla(默认)JS中,这是:
var textareas = document.getElementsByTagName('textarea');
if ( textareas ) {
for ( var i = 0; i < textareas.length; i++ ) {
textareas[i].addEventListener( 'keydown', function ( e ) {
if ( e.which != 9 ) return;
var start = this.selectionStart;
var end = this.selectionEnd;
this.value = this.value.substr( 0, start ) + "\t" + this.value.substr( end );
this.selectionStart = this.selectionEnd = start + 1;
e.preventDefault();
return false;
});
}
}
textarea {
border: 1px solid #cfcfcf;
width: 100%;
margin-left: 0px;
top: 0px;
bottom: 0px;
position: absolute;
}
<textarea>
var x = 10;
var y = 10;
</textarea>
启用在(多个)textarea元素内的制表符
纠正@alexwells答案并启用实时演示
var textAreaArray = document.querySelectorAll("textarea");
for (var i = textAreaArray.length-1; i >=0;i--){
textAreaArray[i].addEventListener('keydown',function(e) {
if(e.keyCode === 9) { // tab was pressed
// get caret position/selection
var start = this.selectionStart;
var end = this.selectionEnd;
var target = e.target;
var value = target.value;
// set textarea value to: text before caret + tab + text after caret
target.value = value.substring(0, start)
+ "\t"
+ value.substring(end);
// put caret at right position again (add one for the tab)
this.selectionStart = this.selectionEnd = start + 1;
// prevent the focus lose
e.preventDefault();
}
},false);
}
<textarea rows="10" cols="80"></textarea>
<textarea rows="10" cols="80"></textarea>
在搜寻google时发现了这个。我做了一个很短的文章,它也可以缩进和缩进所选的文本:
jQ(document).on('keydown', 'textarea', function(e) {
if (e.keyCode !== 9) return;
var Z;
var S = this.selectionStart;
var E = Z = this.selectionEnd;
var A = this.value.slice(S, E);
A = A.split('\n');
if (!e.shiftKey)
for (var x in A) {
A[x] = '\t' + A[x];
Z++;
}
else
for (var x in A) {
if (A[x][0] == '\t')
A[x] = A[x].substr(1);
Z--;
}
A = A.join('\n');
this.value = this.value.slice(0, S) + A + this.value.slice(E);
this.selectionStart = S != E ? S : Z;;
this.selectionEnd = Z;
e.preventDefault();
});