【回忆1314】回忆之placeholder

/**
 * @description: 表单input、textarea占位提示
 * @author:jununx@gmail.com
 * @update: 2014/11/10
 *
 * @param txt{string} 提示信息语句
 *
 * 用法
 *
 * $(‘.J_Placeholder‘).placeholder({
 *     ‘txt‘: ‘请输入提示信息‘
 * });
 */

;(function($){

    var methods = {
        init: function(opts){
            this.isHtml5Placeholder() ? this.changeHtml5Placeholder(opts) : this.changePlaceholder(opts);
        },
        isHtml5Placeholder: function(){
            var res = ‘placeholder‘ in document.createElement(‘input‘);
            return res;
        },
        changePlaceholder: function(opts){
            opts.that.attr(‘value‘) == ‘‘ && opts.that.attr({
                ‘value‘: opts.txt
            });

            opts.that
                .on(‘focus‘, function(){
                    if($(this).val() === opts.txt){
                        $(this).attr(‘value‘, ‘‘);
                    }
                })
                .on(‘blur‘, function(){
                    if($(this).val() == ‘‘){
                        $(this).attr({
                            ‘value‘: opts.txt
                        });
                    }
                });
        },
        changeHtml5Placeholder: function(opts){
            opts.that.attr({
                ‘placeholder‘: opts.txt
            });
        }
    };

    $.fn.placeholder = function(opts){
        opts = $.extend({
            ‘that‘: this,
            ‘txt‘: ‘‘
        }, opts || {});
        methods.init(opts);
        return this;
    };

})(jQuery);