我需要在＆＃34; 41＆＃34;中插入用户输入数字值。 var value = getClosestNum（ 41 ，intarray）;。
我知道＆＃34; 41＆＃34;需要从输入中调用名称或id，但是生锈的Javascript尝试似乎总是以= 1结果。我已经尝试了几个getDocument，getID变体，子函数等，但没有成功。
理想情况下，通过在输入字段上使用onChange而不重新加载页面，结果将是即时的。
是的，以后必须使用JavaScript才能合并。
<html>
<head>
<title>Find nearest value in javascript</title>
<script language="javascript">
// big array to come, example numbers
var intarray=[1,2,3,5,7,9,11,33,40,42,44,55,66,77,88];
// Now this function used to find out the close value in array for given number
function getClosestNum(num, ar)
{
var i = 0, closest, closestDiff, currentDiff;
if(ar.length)
{
closest = ar[0];
for(i;i<ar.length;i++)
{
closestDiff = Math.abs(num - closest);
currentDiff = Math.abs(num - ar[i]);
if(currentDiff < closestDiff)
{
closest = ar[i];
}
closestDiff = null;
currentDiff = null;
}
//returns first element that is closest to number
return closest;
}
//no length
return false;
}
</script>
</head>
<body>
<form>
<input type="number" id="test" name="test" onChange="?">
</form>
<script language="javascript">
document.write("Array: "+intarray+"<br>");
document.write("Value to find 41 <br>");
// CODE TO CHANGE "41" to id or named input
// 41 to reference input field
var value=getClosestNum(41,intarray);
document.write("Response Received "+value);
</script>
</body>
</html>
答案 0 :(得分：0)
你在每个循环中都没有对closestDiff的引用，你需要在整个循环中保留该值并在diff减少时更新它。
function getClosestNum(num, arr) {
var closest;
if (arr.length > 0) {
closest = arr[0];
var diff = Math.abs(arr[0] - num);
for (var i = 1; i < arr.length; i++) {
var currentDiff = Math.abs(arr[i] - num);
if (diff > currentDiff) {
closest = arr[i];
diff = currentDiff;
}
}
}
return closest;
}
答案 1 :(得分：0)
据我了解，您正在尝试使用input元素取一个数字，并且您希望从数组中返回最接近该输入的数字。
我注册了一个触发“＆＃39;输入”的功能。事件。试试这个：
添加以下元素以查看函数的输出。您可以稍后将其重定向到您需要的任何位置。
<p id="output"></p>
// wrap in an onload function to ensure
// that the elements exist before searching for them
window.onload = () => {
// cache of elements on the page you want to use
const testInputElement = document.getElementById('test');
const outputElement = document.getElementById('output');
// create a function that will fire whenever input is received
testInputElement.addEventListener('input', (event) => {
outputElement.innerHTML = getClosestNum(event.target.value, intarray);
})
};
onInput vs addEventListener('input') 将onInput直接添加到元素内的HTML并不像通过addEventListener()以编程方式注册函数那样安全。如果你有一个名为handleInput()的函数，只需将该名称作为参数传递给addEventListener，就像这样
addEventListener('input', handleInput);
<html>
<head>
<title>Find nearest value in javascript</title>
<script language="javascript">
// big array to come, example numbers
var intarray=[1,2,3,5,7,9,11,33,40,42,44,55,66,77,88];
// Now this function used to find out the close value in array for given number
function getClosestNum(num, ar)
{
var i = 0, closest, closestDiff, currentDiff;
if(ar.length)
{
closest = ar[0];
for(i;i<ar.length;i++)
{
closestDiff = Math.abs(num - closest);
currentDiff = Math.abs(num - ar[i]);
if(currentDiff < closestDiff)
{
closest = ar[i];
}
closestDiff = null;
currentDiff = null;
}
//returns first element that is closest to number
return closest;
}
//no length
return false;
}
</script>
</head>
<body>
<form>
<input type="number" id="test" name="test" onChange="?">
</form>
<p id="output"></p>
<script language="javascript">
document.write("Array: "+intarray+"<br>");
document.write("Value to find 41 <br>");
// CODE TO CHANGE "41" to id or named input
// 41 to reference input field
var value=getClosestNum(41,intarray);
document.write("Response Received "+value);
// wrap in an onload function to ensure that the elements exist before searching for them
window.onload = () => {
// cache of elements on the page you want to use
const testInputElement = document.getElementById('test');
const outputElement = document.getElementById('output');
// create a function that will fire whenever input is received
testInputElement.addEventListener('input', (event) => {
outputElement.innerHTML = getClosestNum(event.target.value, intarray);
})
};
</script>
</body>
</html>