JQuery在光标位置插入内容的实现代码

(function($){ 
$.fn.extend({ 
insertAtCaret: function(myValue){ 
var $t=$(this)[0]; 
if (document.selection) { 
this.focus(); 
sel = document.selection.createRange(); 
sel.text = myValue; 
this.focus(); 
} 
else 
if ($t.selectionStart || $t.selectionStart == '0') { 
var startPos = $t.selectionStart; 
var endPos = $t.selectionEnd; 
var scrollTop = $t.scrollTop; 
$t.value = $t.value.substring(0, startPos) + myValue + $t.value.substring(endPos, $t.value.length); 
this.focus(); 
$t.selectionStart = startPos + myValue.length; 
$t.selectionEnd = startPos + myValue.length; 
$t.scrollTop = scrollTop; 
} 
else { 
this.value += myValue; 
this.focus(); 
} 
} 
}) 
})(jQuery);

$(selector).insertAtCaret("value");