如果函數返回相同的輸出

Question

當用戶選擇一個答案，下面的代碼應該產生不同的結果;然而，它只是給出了相同的結果。爲什麼按下按鈕時會得到相同的結果？

1.Is the network problem affecting just your pc? <BR> 

<select id="Area"> 

    <option value="Yes">Yes</option> 

    <option value="No">No</option> 

    </select> 

<br> 

<br><p> 



2.Can you access the internet? <BR> 



<select id="Internet"> 

    <option value="Yes">Yes</option> 

    <option value="No">No</option> 

    <option value="Yes,but is slow">Yes,but is slow</option> 

    <option value="Drop in connection">Drop in connection</option> 

</select> 

<br> 

<br><p> 



3.Are you receiving any error message saying remote system could not be found or connection has timed out?<BR> 

<select id="Errors"> 

    <option value="Remote">Remote system could not be found</option> 

    <option value="Connection">Connection has timed out</option> 

    <option value="No">No error messages </option> 

    </select> 

<br> 

<br><p> 



4.Have you changed any software or Hardware before the problem occurred?<BR> 



<select id="Change"> 

    <option value="Software">Software</option> 

    <option value="Hardware">Hardware</option> 

    <option value="Both">Both</option> 

    <option value="None">None </option> 

</select> 

<br> 

<br><p> 





<button onclick="myFunction()">Detect</button> 



<p id="Solution"></p> 



<script> 

function myFunction() 

{ 

    var AreaElem = document.getElementById("Area"); 

    var Area = AreaElem.options[AreaElem.selectedIndex].value; 

    var InternetElem = document.getElementById("Internet"); 

    var Internet= InternetElem.options[InternetElem.selectedIndex].value; 
    var ErrorsElem = document.getElementById("Errors"); 

    var Errors= ErrorsElem.options[ErrorsElem.selectedIndex].value; 
    var ChangeElem = document.getElementById("Change"); 

    var Change= ChangeElem.options[ChangeElem.selectedIndex].value; 



    if (Area=="Yes"||Internet=="Yes"||Errors=="No"||Change=="No") { 
     x="check your cable is not cut or loose"; 
} else if (Area=="Yes"||Internet=="Yes"||Errors=="No"||Change=="Both") { 
     x="network connections "; 
    } else { 
     x="other problems...."; 
    } 
    document.getElementById("Solution").innerHTML=x; 
} 

</script> 

Answer 1

if (Area=="Yes"||Internet=="Yes"||Errors=="No"||Change=="No") { 
     x="check your cable is not cut or loose"; 
} else if (Area=="Yes"||Internet=="Yes"||Errors=="No"||Change=="Both") { 
     x="network connections "; 
    } else { 
     x="other problems...."; 
    } 

的問題就在這裏！您正在使用「或」操作符||你應該使用「和」運營商&& 這應該解決它

if (Area=="Yes"&&Internet=="Yes"&&Errors=="No"&&Change=="No") { 
     x="check your cable is not cut or loose"; 
} else if (Area=="Yes"&&Internet=="Yes"&&Errors=="No"&&Change=="Both") { 
     x="network connections "; 
    } else { 
     x="other problems...."; 
    }