textarea自动适应内容的高度

时间：2022-08-07 06:00:55

方法一:

<textarea rows=1 cols=40 style='overflow:scroll;overflow-y:hidden;;overflow-x:hidden' 
onfocus="window.activeobj=this;this.clock=setInterval(function(){activeobj.style.height=activeobj.scrollHeight+'px';},200);" onblur="clearInterval(this.clock);"></textarea>

方法二： 

<script>
var agt = navigator.userAgent.toLowerCase();
var is_op = (agt.indexOf("opera") != -1);
var is_ie = (agt.indexOf("msie") != -1) && document.all && !is_op;
function ResizeTextarea(a,row){
    if(!a){return}
    if(!row)
        row=5;
    var b=a.value.split("\n");
    var c=is_ie?1:0;
    c+=b.length;
    var d=a.cols;
    if(d<=20){d=40}
    for(var e=0;e<b.length;e++){
        if(b[e].length>=d){
            c+=Math.ceil(b[e].length/d)
        }
    }
    c=Math.max(c,row);
    if(c!=a.rows){
        a.rows=c;
    }
}
</script>
<textarea style="overflow: hidden;  font-family: Verdana,Arial; font-style: normal;  font-size: 13px; line-height: normal; " rows="4" cols="30" onfocus="javascript:ResizeTextarea(this,4);" onclick="javascript:ResizeTextarea(this,4);" onkeyup="javascript:ResizeTextarea(this,4);"></textarea>


方法三： 

<script type="text/javascript">
    //基本函数*2
    var addHandler = window.addEventListener?
    function(elem,event,handler){elem.addEventListener(event,handler);}:
    function(elem,event,handler){elem.attachEvent("on"+event,handler);};
    var $ = function(id){return document.getElementById(id);}
    function autoTextArea(elemid){
        //新建一个textarea用户计算高度
        if(!$("_textareacopy")){
            var t = document.createElement("textarea");
            t.id="_textareacopy";
            t.style.position="absolute";
            t.style.left="-9999px";
            document.body.appendChild(t);
        }
        function change(){
            $("_textareacopy").value= $(elemid).value;
            $(elemid).style.height= $("_textareacopy").scrollHeight+$("_textareacopy").style.height+"px";
        }
        addHandler($("target"),"propertychange",change);//for IE
        addHandler($("target"),"input",change);// for !IE
        $(elemid).style.overflow="hidden";//一处隐藏，必须的。
        $(elemid).style.resize="none";//去掉textarea能拖拽放大/缩小高度/宽度功能
    }

    addHandler(window,"load",function(){
    autoTextArea("target");
    });
</script>
<textarea id="target" rows="" cols=""></textarea>
</body>
</html>

调试成功案例：

<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">
<head>
</head>
<body>
<textarea rows=1 cols=40 style='overflow:scroll;overflow-y:hidden;;overflow-x:hidden' 
onfocus="window.activeobj=this;this.clock=setInterval(function(){activeobj.style.height=activeobj.scrollHeight+'px';},200);" onblur="clearInterval(this.clock);"></textarea><br/><br/>
<script>
var agt = navigator.userAgent.toLowerCase();
var is_op = (agt.indexOf("opera") != -1);
var is_ie = (agt.indexOf("msie") != -1) && document.all && !is_op;
function ResizeTextarea(a,row){
    if(!a){return}
    if(!row)
        row=5;
    var b=a.value.split("\n");
    var c=is_ie?1:0;
    c+=b.length;
    var d=a.cols;
    if(d<=20){d=40}
    for(var e=0;e<b.length;e++){
        if(b[e].length>=d){
            c+=Math.ceil(b[e].length/d)
        }
    }
    c=Math.max(c,row);
    if(c!=a.rows){
        a.rows=c;
    }
}
</script>
<textarea style="overflow: hidden;  font-family: Verdana,Arial; font-style: normal;  font-size: 13px; line-height: normal; " rows="4" cols="30" onfocus="javascript:ResizeTextarea(this,4);" onclick="javascript:ResizeTextarea(this,4);" onkeyup="javascript:ResizeTextarea(this,4);"></textarea>
</body>
</html>


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