JavaScript本地存储实现用户名存储案例

    <input type="text">
    <button class="set">存储数据</button>
    <button class="get">获取数据</button>
    <button class="remove">删除数据</button>
    <button class="del">清空所有数据</button>
    <script>
        console.log(localStorage.getItem('username'));
 
        var ipt = document.querySelector('input');
        var set = document.querySelector('.set');
        var get = document.querySelector('.get');
        var remove = document.querySelector('.remove');
        var del = document.querySelector('.del');
        set.addEventListener('click', function() {
            // 当我们点击了之后，就可以把表单里面的值存储起来
            var val = ipt.value;
            sessionStorage.setItem('uname', val);
            sessionStorage.setItem('pwd', val);
        });
        get.addEventListener('click', function() {
            // 当我们点击了之后，就可以把表单里面的值获取过来
            console.log(sessionStorage.getItem('uname'));
        });
        remove.addEventListener('click', function() {
            // 
            sessionStorage.removeItem('uname');
        });
        del.addEventListener('click', function() {
            // 当我们点击了之后，清除所有的
            sessionStorage.clear();
        });
    </script>

    <input type="text">
    <button class="set">存储数据</button>
    <button class="get">获取数据</button>
    <button class="remove">删除数据</button>
    <button class="del">清空所有数据</button>
    <script>
        var ipt = document.querySelector('input');
        var set = document.querySelector('.set');
        var get = document.querySelector('.get');
        var remove = document.querySelector('.remove');
        var del = document.querySelector('.del');
        set.addEventListener('click', function() {
            var val = ipt.value;
            localStorage.setItem('username', val);
        })
        get.addEventListener('click', function() {
            console.log(localStorage.getItem('username'));
        })
        remove.addEventListener('click', function() {
            localStorage.removeItem('username');
        })
        del.addEventListener('click', function() {
            localStorage.clear();
 
        })
    </script>

   <input type="text" name="username" id="username" value="" placeholder="请输入用户名"/>
   <input type="checkbox" id="rusername"> 记住用户名
		
   <script type="text/javascript">
        var username = document.querySelector('#username');
		var rusername = document.querySelector('#rusername');
			
		// 先判断用户是否需要记录数据 再让记录的数据显示再表单里面 
		if(localStorage.getItem('username')){
			username.value=localStorage.getItem('username');
			rusername.checked = true;
		}
		// change改变时 发生  Checkbox选中和不选中时 发生
		rusername.addEventListener('change',function(){
			// console.log('改变了');
			// console.log(rusername.checked);
			if(this.checked){
				localStorage.setItem('username',username.value);
			}else{
				localStorage.removeItem('username');
			}
		})
	</script>