提示用户输入，但在表单上显示输入
提示用户输入，但在表单上显示输入
提问于 2020-10-20 01:17:46
早上好,
有人知道如何更正下面的代码吗？首先，我提示用户输入变量first和second，但未能在表单上显示它们。其次，当用户单击Determine the larger number按钮时，它应该运行位于function determineLarge(){下的if和else if语句，但它无法运行。我很抱歉，因为我正在大学里学习如何编写这门语言。谢谢你的帮助。
<script>
function determineLarge(){
let first = prompt ("Enter the first number.");
first= document.myForm.first.value;
let second = prompt("Enter the second number.");
second =document.myForm.first.value;
first = parseFloat(first);
second = parseFloat(second);
let message = "";
if (first <0 || second <0){
message = "You can't use negative numbers.";
}
else if (first > second){
message = "The second number" + "(" + second + ")" + " is smaller.";
}
else if (second > first) {
message = "The first number" + "(" + first + ")" + " is smaller.";
}
else if (first == second || second==first){
message = "The first number" + "(" + first + ")" + " is smaller.";
}
document.getElementById("results").innerHTML = message;
}
</script>
</head>
<body>
<h1>Gary's Smaller of Two Numbers</h1>
<form name="myForm">
<p> Enter the first number</p>
<input type="number" name="first" value="" onclick="javascript:determineLarge();">
<p>Enter the second number</p>
<input type="number" name="second" value="" onclick="javascript:determineLarge();">
<button type="button" onclick="determineLarge();">Determine the larger number</button>
</form>
<div id="results"> </div>
</body>回答 2
Stack Overflow用户
发布于 2020-10-20 01:27:20
我将值的获取和处理分成了两个函数。
我将提示符放在一个while循环中，这样您就必须输入一个大于零的实际值。
另外，您可以通过保留变量名的第一个来覆盖第一个和第二个变量，例如: first = ....而不是document.myform.value == first等等。
first = -1;
second = -1;
function getValues(){
while(isNaN(first) || first == "" || first < 0){
first = prompt ("Enter the first number.");
}
while(isNaN(second) || second == "" || second < 0){
second = prompt ("Enter the second number.");
}
document.myForm.first.value = first;
document.myForm.second.value = second;
}
function determineLarge(){
let message = "";
if (first > second){
message = "The second number" + "(" + second + ")" + " is smaller.";
}
else if (second > first) {
message = "The first number" + "(" + first + ")" + " is smaller.";
}
else if (first == second || second==first){
message = "The first number" + "(" + first + ")" + " is smaller.";
}
document.getElementById("results").innerHTML = message;
}<h1>Gary's Smaller of Two Numbers</h1>
<form name="myForm">
<p> Enter the first number</p>
<input type="number" name="first" value="" onclick="javascript:getValues();">
<p>Enter the second number</p>
<input type="number" name="second" value="" onclick="javascript:getValues();">
<button type="button" onclick="determineLarge();">Determine the larger number</button>
</form>
<div id="results"> </div>
Stack Overflow用户
发布于 2020-10-20 01:32:51
我删除了提示符，以便可以使用输入。不需要在文本输入上调用onClick。
<script>
function determineLarge(myForm) {
var first = myForm.first.value;
var second = myForm.second.value;
console.log(first, second)
first = parseFloat(first);
second = parseFloat(second);
let message = "";
if (first < 0 || second < 0) {
message = "You can't use negative numbers.";
} else if (first > second) {
message = "The second number" + "(" + second + ")" + " is smaller.";
} else if (second > first) {
message = "The first number" + "(" + first + ")" + " is smaller.";
} else if (first == second || second == first) {
message = "The first number" + "(" + first + ")" + " is smaller.";
}
document.getElementById("results").innerHTML = message;
}
</script>
</head>
<body>
<h1>Gary's Smaller of Two Numbers</h1>
<form name="myForm">
<p> Enter the first number</p>
<input type="number" name="first" value="">
<p>Enter the second number</p>
<input type="number" name="second" value="">
<button type="button" onclick="determineLarge(this.form);">Determine the larger number</button>
</form>
<div id="results"> </div>
</body>
页面原文内容由Stack Overflow提供。腾讯云小微IT领域专用引擎提供翻译支持
原文链接：
https://stackoverflow.com/questions/64432249
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