开关情况简单的例子没有反映在段落

我在JavaScript中有一个简单的开关案例的例子。虽然，段落中的价值应该反映为开关案例中的第三种选择，但它没有显示任何内容或空白段落。 Pl，帮忙！开关情况简单的例子没有反映在段落

<html> 
 
<head></head> 
 
<body> 
 
<p id="para1"></p> 
 
<script> 
 
var i = 3; 
 
switch(i){ 
 
case 1: { 
 
\t document.getElementById('para1').value = "The value is one."; 
 
\t break; 
 
} 
 
case 2: { 
 
\t document.getElementById('para1').value = "The value is two."; 
 
\t break; 
 
} 
 
case 3: { 
 
\t document.getElementById('para1').value = "The value is three."; 
 
\t break; 
 
} 
 
default:{ 
 
\t document.getElementById('para1').value = "The value is undefined." 
 
} 
 
} 
 
</script> 
 
</body> 
 
</html>

来源

2017-05-12 Deadpool

innerHTML的不珍惜 –

p在不input元素标签，因此它不具有value。您应该使用innerHTML来设置值。


             
   
    
    <html> 
 
    <head></head> 
 
    <body> 
 
    <p id="para1"></p> 
 
    <script> 
 
    var i = 3; 
 
    switch(i){ 
 
    case 1: { 
 
    \t document.getElementById('para1').innerHTML = "The value is one."; 
 
    \t break; 
 
    } 
 
    case 2: { 
 
    \t document.getElementById('para1').innerHTML = "The value is two."; 
 
    \t break; 
 
    } 
 
    case 3: { 
 
    \t document.getElementById('para1').innerHTML = "The value is three."; 
 
    \t break; 
 
    } 
 
    default:{ 
 
    \t document.getElementById('para1').innerHTML = "The value is undefined." 
 
    } 
 
    } 
 
    </script> 
 
    </body> 
 
    </html>

来源

2017-05-12 06:47:49

使用innerHTML替代值：

<html> 
 
<head></head> 
 
<body> 
 
<p id="para1"></p> 
 
<script> 
 
var i = 3; 
 
switch(i){ 
 
case 1: { 
 
\t document.getElementById('para1').innerHTML = "The value is one."; 
 
\t break; 
 
} 
 
case 2: { 
 
\t document.getElementById('para1').innerHTML = "The value is two."; 
 
\t break; 
 
} 
 
case 3: { 
 
\t document.getElementById('para1').innerHTML = "The value is three."; 
 
\t break; 
 
} 
 
default:{ 
 
\t document.getElementById('para1').innerHTML = "The value is undefined." 
 
} 
 
} 
 
</script> 
 
</body> 
 
</html>

来源

2017-05-12 06:49:07

var i = 3; 
 
switch(i){ 
 
case 1: { 
 
\t document.getElementById('para1').innerHTML = "The value is one."; 
 
\t break; 
 
} 
 
case 2: { 
 
\t document.getElementById('para1').innerHTML = "The value is two."; 
 
\t break; 
 
} 
 
case 3: { 
 
\t document.getElementById('para1').innerHTML = "The value is three."; 
 
\t break; 
 
} 
 
default:{ 
 
\t document.getElementById('para1').innerHTML = "The value is undefined." 
 
} 
 
}

<p id="para1">test</p>

来源

2017-05-12 06:49:57 Icewine

请给予解释。只是给出答案不利于他/她。 –

开关情况简单的例子没有反映在段落

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