jquery----TextArea高度自適應

 //最小高度和最大高度默認
  $("#textarea1").textareaAutoHeight();
  //最大高度為100px
  $("#textarea2").textareaAutoHeight({ maxHeight:100 });
  //最小高度為50px，最大高度為200px
  $("#textarea3").textareaAutoHeight({ minHeight:50, maxHeight:200 });

$.fn.extend({
    textareaAutoHeight: function (options) {
        this._options = {
            minHeight: 0,
            maxHeight: 1000
        }

    this.init = function () {
        for (var p in options) {
            this._options[p] = options[p];
        }
        if (this._options.minHeight == 0) {
            this._options.minHeight=parseFloat($(this).height());
        }
        for (var p in this._options) {
            if ($(this).attr(p) == null) {
                $(this).attr(p, this._options[p]);
            }
        }
        $(this).keyup(this.resetHeight).change(this.resetHeight)
        .focus(this.resetHeight);
    }
    this.resetHeight = function () {
        var _minHeight = parseFloat($(this).attr("minHeight"));
        var _maxHeight = parseFloat($(this).attr("maxHeight")); 

        if (!$.browser.msie) {
            $(this).height(0);
        }
        var h = parseFloat(this.scrollHeight);
        h = h < _minHeight ? _minHeight :
                    h > _maxHeight ? _maxHeight : h;
        $(this).height(h).scrollTop(h);
        if (h >= _maxHeight) {
            $(this).css("overflow-y", "scroll");
        }
        else {
            $(this).css("overflow-y", "hidden");
        }
    }
    this.init();
}

}); </pre>