前端事件案例补充
目录
定时器示例
搜索框示例
省市联动
定时器示例
<!DOCTYPE html>
<html lang="en">
<head><meta charset="UTF-8"><title>Title</title><meta name="viewport" content="width=device-width, initial-scale=1">
</head>
<body>
<input type="text" id="i1">
<button id="b1">开始</button>
<button id="b2">结束</button><script>var t;function showTime() {var i1Ele = document.getElementById('i1');var time = new Date();i1Ele.value = time.toLocaleString();}showTime();var b1Ele = document.getElementById('b1');b1Ele.onclick = function (ev) {if (!t){t = setInterval(showTime,1000)}};var b2Ele = document.getElementById('b2');b2Ele.onclick = function (ev) {clearInterval(t);t = undefined};</script>
</body>
</html>搜索框示例
<!DOCTYPE html>
<html lang="en">
<head><meta charset="UTF-8"><title>搜索框示例</title></head>
<body>
<input id="d1" type="text" username="aa" placeholder="请输入关键字" onblur=
"blur1()" onfocus="focus1()"><script>function focus1() {var inputEle = document.getElementById("d1");var placehold=inputEle.getAttribute('placeholder');console.log(placehold);// if (inputEle.value === "请输入关键字") {if (placehold === "请输入关键字") {inputEle.value = "";}}function blur1() {var inputEle = document.getElementById("d1");// var val = inputEle.value;var val=inputEle.getAttribute('placeholder');if (!val.trim()) {// inputEle.value = "请输入关键字";inputEle.setAttribute('placeholder', '请输入关键字111'); // 如何去修改标签的属性}}
</script>
</body>
</html>省市联动
<!DOCTYPE html>
<html lang="en">
<head><meta charset="UTF-8"><meta http-equiv="x-ua-compatible" content="IE=edge"><meta name="viewport" content="width=device-width, initial-scale=1"><title>select联动</title></head>
<body>
<select name="" id="province"><option value="">请选择</option></select><select name="" id="city"><option value="">请选择</option>
</select><script>var data = {"河北省": ["廊坊", "邯郸", "保定", "石家庄"],"北京": ["朝阳区", "海淀区", "大兴区", "通州区"],"河南省": ["郑州", "周口", "信阳", "洛阳"],"江苏省": ["南京", "苏州", "徐州", "无锡"],"浙江省": ["杭州", "绍兴", "温州", "嘉兴"],"上海": ["黄浦区", "普陀区", "闵行区", "浦东新区"],};var province = document.getElementById('province');var city = document.getElementById('city');// 1. 要循环data数据，拿到data数据的key值是省作为第一个下拉框的数据for (var i in data) {// 这里的i值就是data 的key值，其实就是省数据// console.log(data[i])// 2. 创建option标签，怎么样创建标签var option = document.createElement('option');// 3. 给option标签设置value值和文本数据option.value = i; // <option value="河北省">河北省</option>option.innerText = i; // <option value="北京">北京</option>// 4. 把option追加到省的select中取province.appendChild(option);}// 接下来给省的下拉框绑定事件province.onchange = function () {// 1. 先拿到当前用户选择的是哪个省的数据// var current_province = province.value;var current_province = this.value;// 2. 根据选择的省获取对应的市信息var current_city_list = data[current_province]; // ["朝阳区", "海淀区", "大兴", "通州"],city.innerText = '';// 3. 循环的把获取到的所有市列表放到第二个select框去for (var i = 0; i < current_city_list.length; i++) {var option = document.createElement('option'); // <option value=""></option>// 4. 给city标签设置value值和文本数据option.value = current_city_list[i];option.innerText = current_city_list[i];// 5. 把city追加到省的select中取city.appendChild(option);}}</script>
</body>
</html>