本题展示了一个简化版的计算器,需求如下:1、除法操作时,如果被除数为0,则结果为02、结果如果为小数,最多保留小数点后两位,如 2 3 = 0.67(显示0.67), 1 2 = 0.5(显示0.5)3、请阅读并根据提示补充完成函数initEvent、result和calculate4、请不要手动修改html和css5、不要使用第三方插件
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body, ul, li,select { margin: 0; padding: 0; box-sizing: border-box; } ul,li {list-style: none;} .calculator { max-width: 300px; margin: 20px auto; border: 1px solid #eee; border-radius: 3px; } .cal-header { font-size: 16px; color: #333; font-weight: bold; height: 48px; line-height: 48px; border-bottom: 1px solid #eee; text-align: center; } .cal-main { font-size: 14px; } .cal-main .origin-value { padding: 15px; height: 40px; line-height: 40px; font-size: 20px; text-align: right; overflow: hidden; text-overflow:ellipsis; white-space: nowrap; } .cal-main .origin-type, .cal-main .target-type { padding-left: 5px; width: 70px; font-size: 14px; height: 30px; border: 1px solid #eee; background-color: #fff; vertical-align: middle; margin-right: 10px; border-radius: 3px; } .cal-keyboard { overflow: hidden; } .cal-items { overflow: hidden; } .cal-items li { user-select: none; float: left; display: inline-block; width: 75px; height: 75px; text-align: center; line-height: 75px; border-top: 1px solid #eee; border-left: 1px solid #eee; box-sizing: border-box; } li:nth-of-type(4n+1) { border-left: none; } li[data-action=operator] { background: #f5923e; color: #fff; } .buttons { float: left; width: 75px; } .buttons .btn { width: 75px; background-color: #fff; border-top: 1px solid #eee; border-left: 1px solid #eee; height: 150px; line-height: 150px; text-align: center; } .btn-esc { color: #ff5a34; } .btn-backspace { position: relative; }
<div class="calculator"> <header class="cal-header">简易计算器</header> <main class="cal-main"> <div class="origin-value">0</div> <div class="cal-keyboard"> <ul class="cal-items"> <li data-action="num">7</li> <li data-action="num">8</li> <li data-action="num">9</li> <li data-action="operator">÷</li> <li data-action="num">4</li> <li data-action="num">5</li> <li data-action="num">6</li> <li data-action="operator">x</li> <li data-action="num">1</li> <li data-action="num">2</li> <li data-action="num">3</li> <li data-action="operator">-</li> <li data-action="num">0</li> <li data-action="operator">清空</li> <li data-action="operator">=</li> <li data-action="operator">+</li> </ul> </div> </main> </div>
var Calculator = { init: function () { var that = this; if (!that.isInited) { that.isInited = true; // 保存操作信息 // total: Number, 总的结果 // next: String, 下一个和 total 进行运算的数据 // action: String, 操作符号 that.data = {total: 0, next: '', action: ''}; that.bindEvent(); } }, bindEvent: function () { var that = this; // 请补充代码:获取 .cal-keyboard 元素 var keyboardEl = null; keyboardEl && keyboardEl.addEventListener('click', function (event) { // 请补充代码:获取当前点击的dom元素 var target = null; // 请补充代码:获取target的 data-action 值 var action = ''; // 请补充代码:获取target的内容 var value = ''; if (action === 'num' || action === 'operator') { that.result(value, action === 'num'); } }); }, result: function (action, isNum) { var that = this; var data = that.data; if (isNum) { data.next = data.next === '0' ? action : (data.next + action); !data.action && (data.total = 0); } else if (action === '清空') { // 请补充代码:设置清空时的对应状态 data.total = undefined; data.next = undefined; data.action = undefined; } else if (action === '=') { if (data.next || data.action) { data.total = that.calculate(data.total, data.next, data.action); data.next = ''; data.action = ''; } } else if (!data.next) { data.action = action; } else if (data.action) { data.total = that.calculate(data.total, data.next, data.action); data.next = ''; data.action = action; } else { data.total = +data.next || 0; data.next = ''; data.action = action; } // ���补充代码:获取 .origin-value 元素 var valEl = null; valEl && (valEl.innerHTML = data.next || data.total || '0'); }, calculate: function (n1, n2, operator) { n1 = +n1 || 0; n2 = +n2 || 0; if (operator === '÷') { // 请补充代码:获取除法的结果 return 0; } else if (operator === 'x') { // 请补充代码:获取乘法的结果 return 0; } else if (operator === '+') { // 请补充代码:获取加法的结果 return 0; } else if (operator === '-') { // 请补充代码:获取减法的结果 return 0; } } }; Calculator.init();