ie7 input 的提示兼容

if (!('placeholder' in document.createElement('input'))) {

        $('input[placeholder],textarea[placeholder]').each(function () {
            var that = $(this),
                text = that.attr('placeholder');
            if (that.val() === "") {
                that.val(text).addClass('placeholder');
            }
            that.focus(function () {
                if (that.val() === text) {
                    that.val("").removeClass('placeholder');
                }
            })
                .blur(function () {
                    if (that.val() === "") {
                        that.val(text).addClass('placeholder');
                    }
                })
                .closest('form').submit(function () {
                    if (that.val() === text) {
                        that.val('');
                    }
                });
        });
    }

 

var JPlaceHolder = {
        //检测
        _check: function () {
            return 'placeholder' in document.createElement('input');
        },
        //初始化
        init: function () {
            if (!this._check()) {
                this.fix();
            }
        },
        //修复
        fix: function () {
            jQuery(':input[placeholder]').each(function (index, element) {
                var self = $(this), txt = self.attr('placeholder');
                self.wrap($('<div></div>').css({ position: 'relative', zoom: '1', border: 'none', background: 'none', padding: 'none', margin: 'none' }));
                var pos = self.position(), h = self.outerHeight(true), paddingleft = self.css('padding-left');
                var holder = $('<span></span>').text(txt).css({ position: 'absolute', left: pos.left, top: pos.top, height: h, lienHeight: h, paddingLeft: paddingleft, color: '#aaa' }).appendTo(self.parent());
                self.focusin(function (e) {
                    holder.hide();
                }).focusout(function (e) {
                    if (!self.val()) {
                        holder.show();
                    }
                });
                holder.click(function (e) {
                    holder.hide();
                    self.focus();
                });
            });
        }
    };
    //执行
    jQuery(function () {
        JPlaceHolder.init();
    });