在下一个函数中使用选项中的变量

问题描述 投票:0回答:2

我试图通过从期权中获得价值来解决问题。当我从中选择一个数字时,该数字在p标签中正确打印,并且让index也正确,但是我想在该程序的下一个函数中使用'const n'。仅出于测试目的,我创建了函数send()进行检查,我可以使用此变量,但console.log始终为NaN。我该如何解决?

<p id="p">Your number is: 0</p>

<select id="select">
  <option>1</option>
  <option>2</option>
  <option>3</option>
  <option>4</option>
  <option>5</option>
</select>

<button onclick="send();">SEND</button>


//JS
var selectElem = document.getElementById('select')
    var pElem = document.getElementById('p')


const n = selectElem.addEventListener('change', function() {
  let index = selectElem.value;

  pElem.innerHTML = 'Your number is: ' + index;
  return index;

})

console.log(n);
const a  = n*2;
function send(){
  console.log('-----');
  console.log(n);
  console.log(a);
}
javascript select option
2个回答
0
投票

//JS var selectElem = document.getElementById('select') var pElem = document.getElementById('p') var obj ={ n:'weqwe' } function setN(n){ obj.n =n } selectElem.addEventListener('change', function(obj) { let index = selectElem.value; setN( selectElem.value); pElem.innerHTML = 'Your number is: ' + index; return index; }) function send(){ console.log(obj.n) }
<!DOCTYPE html> <html> <head> <meta charset="utf-8"> <meta name="viewport" content="width=device-width"> <title>JS Bin</title> </head> <body> <p id="p">Your number is: 0</p> <select id="select"> <option>1</option> <option>2</option> <option>3</option> <option>4</option> <option>5</option> </select> <button onclick="send();">SEND</button> </body> </html>
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