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//截获了Tab按键,其他的textarea框不进行此配置
//下面的代码就是为了实现这个功能,原理很简单,采用上一行的缩进就行
//只要在html中插入脚本调用set_tab_indent_for_textareas()函数就可以了
//注1:需要jQuery支持,如果不喜欢jQuery改成裸javascript也很方便的
//兼容firefox和IE!
/*------selection operations-------*/
function insertAtCursor(obj, txt) {
obj.focus();
//IE support
if (document.selection) {
sel = document.selection.createRange();
sel.text = txt;
}
//MOZILLA/NETSCAPE support
else {
var startPos = obj.selectionStart;
var scrollTop = obj.scrollTop;
var endPos = obj.selectionEnd;
obj.value = obj.value.substring(0, startPos) + txt + obj.value.substring(endPos, obj.value.length);
startPos += txt.length;
obj.setSelectionRange(startPos, startPos);
obj.scrollTop = scrollTop;
}
}
function getCaretPos(ctrl) {
var caretPos = 0;
if (document.selection) {
// IE Support
var range = document.selection.createRange();
// We'll use this as a 'dummy'
var stored_range = range.duplicate();
// Select all text
stored_range.moveToElementText(ctrl);
// Now move 'dummy' end point to end point of original range
stored_range.setEndPoint('EndToEnd', range);
// Now we can calculate start and end points
ctrl.selectionStart = stored_range.text.length - range.text.length;
ctrl.selectionEnd = ctrl.selectionStart + range.text.length;
caretPos = ctrl.selectionStart;
} else if (ctrl.selectionStart || ctrl.selectionStart == '0')
// Firefox support
caretPos = ctrl.selectionStart;
return (caretPos);
}
function getCurrentLineBlanks(obj) {
var pos = getCaretPos(obj);
var str = obj.value;
var i = pos - 1;
while (i >= 0) {
if (str.charAt(i) == '\n')
break;
i--;
}
i++;
var blanks = "";
while (i < str.length) {
var c = str.charAt(i);
if (c == ' ' || c == '\t')
blanks += c;
else
break;
i++;
}
return blanks;
}
function set_tab_indent_for_textareas() {
/* set all the tab indent for all the text areas */
$("textarea").each(function() {
$(this).keydown(function(eve) {
if (eve.target != this) return;
if (eve.keyCode == 13)
last_blanks = getCurrentLineBlanks(this);
else if (eve.keyCode == 9) {
eve.preventDefault();
insertAtCursor(this, " ");
this.returnValue = false;
}
}).keyup(function(eve) {
if (eve.target == this && eve.keyCode == 13)
insertAtCursor(this, last_blanks);
});
});
}
</script>
共享一下,请大家提出修改意见。
<textarea id='tabTest' style="width:500px;height:200px;" onkeydown='testTab()'></textarea>
<SCRIPT LANGUAGE="JavaScript">
<!--
function testTab() {
var sel = document.selection.createRange();
if (event.shiftKey && event.keyCode == 9) {
sel.move("character", -4);
sel.select();
event.returnValue = false;
return;
}
if (event.keyCode == 9) {
sel.text = "\u0020\u0020\u0020\u0020";
//sel.move("character",4);
sel.select();
event.returnValue = false;
}
}
//-->
</SCRIPT>
<script language="JavaScript">
<!--
function testTab() {
var sel = document.selection.createRange();
var mytext = sel.text;
var i, j, k;
if (event.shiftKey && event.keyCode == 9) {
arr = mytext.split(String.fromCharCode(13, 10))
mytext = ""
for (k = 0; k < arr.length; k++) {
for (j = 1; j <= 4; j++) {
if (arr[k].substr(0, 1) == "\u0020") {
arr[k] = arr[k].slice(1)
}
}
mytext += arr[k] + ((k == (arr.length - 1)) ? "" : String.fromCharCode(13, 10));
}
with (sel) {
sel.text = mytext;
collapse(true)
moveEnd("character", 0)
moveStart("character", (mytext.length) * -1)
select()
}
window.event.cancelBubble = true;
event.returnValue = false;
return;
}
if (event.keyCode == 9) {
arr = mytext.split(String.fromCharCode(13, 10))
mytext = ""
for (j = 0; j < arr.length; j++) {
mytext += "\u0020\u0020\u0020\u0020" + arr[j] + ((j == (arr.length - 1)) ? "" : String.fromCharCode(13, 10));
}
with (sel) {
sel.text = mytext;
collapse(true)
moveEnd("character", 0)
moveStart("character", (mytext.length - 4) * -1)
select()
}
window.event.cancelBubble = true;
event.returnValue = false;
return;
}
}
//-->
</script>