[英]Not able to pass variable from one function to another in Javascript
Java和HTML的新手。 簡而言之，如果用戶輸入正確的隨機數學問題總和，則嘗試更新分數。 無法將問題的答案傳遞給我的函數，該函數檢查用戶輸入的內容是否正確。 我只想分數增加一分。 由於某種原因，我無法將參數“ score”傳遞給該函數。 這是我的代碼的一個非常簡單的示例。 更關注邏輯而不是程序的外觀。 我知道現在分數不會正確更新，但是問題出在“答案”變量的傳遞上。 一旦至少調用了該函數，我將輕松完成分數的提高。 非常感謝您的寶貴時間！
<html>
<title></title>
<head>
<link rel="stylesheet" type="text/css" href="style.css">
</head>
<body onload = "displayProblem()">
<script>
function displayProblem(){
var answer = (firstNum) + (secondNum);
var firstNum = (Math.floor(Math.random()*10) + 1);
var secondNum = (Math.floor(Math.random()*10) + 1);
document.getElementById("qstns").innerHTML = firstNum +" + " + secondNum +" = ";
}
function checkAnswer(){
var userAnswer = document.getElementById("answr").value;
if(userAnswer === answer){
updateScore();
console.log("score updated");
}
console.log("did not update score");
}
function displayNext(){
document.getElementById("next").style.display = "block";
}
function hideNext(){
document.getElementById("next").style.display = "none";
}
function updateScore(){
var score = 0;
score++;
document.getElementById("score").innerHTML = score;
}
function clearAnswer(){
document.getElementById("answr").value = " ";
}
</script>
<div id="main">
<div id="qstns">
</div>
</div>
<input type="text" id="answr">
Score: <label id="score"> 0 </label>
<button type="Sumbit" id="submit" onclick="displayNext(), checkAnswer ()">Check</button>
<button type="Submit" id="next" onclick="displayProblem(), hideNext(), clearAnswer()" style="display:none;">Next</button>
</body>
</html>
問題是，每次調用函數“ updateScore”時，都會將“ score”的值重置為零。
一種方法可能是：先閱讀當前分數而不是增加...
function updateScore(){
var score = pareseInt(document.getElementById("score").innerHTML);
score++;
document.getElementById("score").innerHTML = score;
}
或者這樣：將得分設置為“全球”，而不是提高...
var score = 0;
function updateScore(){
score++;
document.getElementById("score").innerHTML = score;
}
嘗試這個：
<html>
<title></title>
<head>
</head>
<body onload="displayProblem()">
<script>
var answer;
var score=0;
function displayProblem(){
var firstNum = (Math.floor(Math.random()*10) + 1);
var secondNum = (Math.floor(Math.random()*10) + 1);
answer = (firstNum) + (secondNum);
document.getElementById("qstns").innerHTML = firstNum +" + " + secondNum +" = ";
}
function checkAnswer(){
var userAnswer = document.getElementById("answr").value;
if(userAnswer == answer)
updateScore();
}
function displayNext(){
document.getElementById("next").style.display = "block";
}
function hideNext(){
document.getElementById("next").style.display = "none";
}
function updateScore(){
score++;
document.getElementById("score").innerHTML = score;
}
function clearAnswer(){
document.getElementById("answr").value = " ";
}
</script>
<div id="main">
<div id="qstns"></div>
</div>
<input type="text" id="answr">Score: <label id="score"> 0 </label></input>
<button type="Sumbit" id="submit" onclick="displayNext(), checkAnswer ()">Check</button>
<button type="Submit" id="next" onclick="displayProblem(), hideNext(), clearAnswer()" style="display:none;">Next</button>
</body>
</html>
您有兩個問題； 一個answer是displayProblem()的局部變量，因此checkAnswer()無法訪問checkAnswer() ，而另一個answer是您使用===而不是== 。 ===計算類型和值， userAnswer和answer是不同類型的，因此它的計算結果為false 。
編輯： score將按預期增加。
<html>
<title></title>
<head>
<link rel='stylesheet' type='text/css' href='style.css'>
</head>
<body onload = 'displayProblem()'>
<script>
//'answer','score' variables should be declared outside function globally
var answer=0;
var score=0;
function displayProblem(){
//var answer = (firstNum) + (secondNum); The calculation should be after assigning value to 'firstNum', 'secondNum'
var firstNum = (Math.floor(Math.random()*10) + 1);
var secondNum = (Math.floor(Math.random()*10) + 1);
answer = (firstNum) + (secondNum);
document.getElementById('qstns').innerHTML = firstNum +' + ' + secondNum +' = ';
}
function checkAnswer(){
var userAnswer = document.getElementById('answr').value;
if(userAnswer == answer){
updateScore();
console.log('score updated');
}
else
console.log('did not update score');
}
function displayNext(){
document.getElementById('next').style.display = 'block';
}
function hideNext(){
document.getElementById('next').style.display = 'none';
}
function updateScore(){
score++;
document.getElementById('score').innerHTML = score;
}
function clearAnswer(){
document.getElementById('answr').value = ' ';
}
</script>
<div id='main'>
<div id='qstns'>
</div>
</div>
<input type='text' id='answr'>
Score: <label id='score'> 0 </label>
<button type='Sumbit' id='submit' onclick='displayNext(), checkAnswer();'>Check</button>
<button type='Submit' id='next' onclick='displayProblem(), hideNext(), clearAnswer();' style='display:none;'>Next</button>
</body>
</html>
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