開關情況簡單的例子沒有反映在段落

我在JavaScript中有一個簡單的開關案例的例子。雖然，段落中的價值應該反映爲開關案例中的第三種選擇，但它沒有顯示任何內容或空白段落。 Pl，幫忙！開關情況簡單的例子沒有反映在段落

<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>

來源

2017-05-12 Deadpool

innerHTML的不珍惜 –

p在不input元素標籤，因此它不具有value。您應該使用innerHTML來設置值。


             
   
    
    <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>

來源

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>

來源

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>

來源

2017-05-12 06:49:57 Icewine

請給予解釋。只是給出答案不利於他/她。 –

開關情況簡單的例子沒有反映在段落

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