document.all判断ie，我这样为何不行？

Question

总是提示错误，可能是因为document.all后面的选项中多了一些分号，那如何改进呢？谢谢

Answer 1

      function input_defaultValue() {                var get_input = document.getElementsByTagName("input");                for(var i = 0; i < get_input.length; i++) {                    if(document.all) {
                        get_input[i].attachEvent('onfocus', function() {                            if(this.value == this.defaultValue) {                                this.value = '';
                            }
                        });
                        get_input[i].attachEvent('onblur', function() {                            if(this.value == '') {                                this.value = this.defaultValue;
                            }
                        });
                    } else {
                        get_input[i].addEventListener('focus', function() {                            if(this.value == this.defaultValue) {                                this.value = '';
                            }
                        });
                        get_input[i].addEventListener('blur', function() {                            if(this.value == '') {                                this.value = this.defaultValue;
                            }
                        });
                    };
                }
            };
            input_defaultValue();

就改成了if（）{}就对了，也没细看。
改进的话当然是能力检测了

            if(document.addEventListener) {                //
            } else if(document.attachEvent()) {                //
            } else {

            }