根据光标位置在字符中插入新的字符

写的比较乱,各位看官就将就吧

<script>

function tellPoint() {

var rng = event.srcElement.createTextRange();

rng.moveToPoint(event.x, event.y);

rng.moveStart("character", -event.srcElement.value.length)

pnum.value = rng.text.length

t.innerText = rng.text;

var str=rng.text;

var insertStr="!!!!!!!!这是插入的字符!!!!!!!!!"

var str1=box.value.substr(rng.text.length,(box.value.length-rng.text.length))

box2.value=str+insertStr+str1;

}

</script>

<textarea rows = "7" cols = "49" id = "box" onclick = tellPoint()>我怕来不及我要抱着你，直到感觉你的绉纹有了岁月的痕迹，直到视线变得模糊直到不能呼吸

</textarea><br>

光标位置：<input type = "text" value = "0" id = "pnum" size = "8"><br>

text:<span style = "position: absolute; z-index: 10" id = "t"></span>

<br>

<br>

<br>

<textarea id="box2" rows = "7" cols = "49">

</textarea>