!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=10 titleDocumenttitle hea

在这段代码中，有一个拼写错误。应该是sessionStorage.setItem("username",val);而不是sessionStorage.setltem("username",val);。所以正确的代码应该是：

<!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=1.0"> 
    <title>Document</title> 
</head> 
<body> 
    <input type="text" id="username"> 
    <button id="setData">设置数据</button> 
    <script> 
        var username=document.querySelector("#username"); 
        document.querySelector("#setData").onclick=function(){ 
            var val =username.value; 
            sessionStorage.setItem("username",val); 
        } 
    </script> 
</body> 
</html>

这样就可以正确地将输入框的值存储在sessionStorage中。

!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=10 titleDocumenttitle hea