纯javascript检测数字输入值的变化 [英] pure javascript detect change in number typed input value
本文介绍了纯javascript检测数字输入值的变化的处理方法,对大家解决问题具有一定的参考价值,需要的朋友们下面随着小编来一起学习吧!
问题描述
< pre class = snippet-code-js lang-js prettyprint-override>
window.onload = function init(){console.log( DOM就绪!); var输入,值;输入= document.getElementById( yourGuess);输入= input.value; input.addEventListener( checking,check,false);检查(值); }功能检查(值){if(输入< 0&&输入> 10){alert(数字必须在0-10之间);值= 0; }}
< label for = yourGuess>您选择:< / label><输入id = yourGuess type = number min = 0 max = 10>
我在任何地方都找不到与上述问题相对应的解决方案。
因此,我有一个数字类型输入,并声明了一个分别为0和10的min和max属性。
用户可以单击输入字段并在其外部更改其值范围,因此我需要使用javasricpt检查所做的任何更改
解决方案
- 您正在使用字符串值覆盖
HTMLInputElement
,因此会出现错误。 - 使用
onchange
事件以及document.addEventListener
。 - 我已经
DOMContentLoaded
方法可以为您提供更好的主意,而不是使用window.onload
!
document.addEventListener('DOMContentLoaded',function(){document。 querySelector(#yourGuess)。onchange = check;},false);函数check(event){if(event.target.value> 10 || event.target.value< 0){alert(数字必须介于0到10之间); event.target.value = 0; }}
< label for = yourGuess>您选择:< / label><输入id = yourGuess type = number min = 0 max = 10>
window.onload = function init() {
console.log("DOM is ready!");
var input, value;
input = document.getElementById("yourGuess");
input = input.value;
input.addEventListener("checking", check, false);
check(value);
}
function check(value) {
if(input < 0 && input > 10) {
alert("The number must be between 0 - 10");
value = 0;
}
}
<label for="yourGuess">You choose: </label>
<input id="yourGuess" type="number" min="0" max="10">
I can't find any solution anywhere that correspond to the issue above.
So I have a number type input and declared a min and max attribute with the value 0 and 10 respectively.
The user can click the input field and change its value outside of range, hence I need to use javasricpt to check any changes made
解决方案
- You're overwritting your
HTMLInputElement
with the value which is string, hence you're getting error. - Use
onchange
event along withdocument.addEventListener
. - I've
DOMContentLoaded
method which gives you better idea instead of usingwindow.onload
!
document.addEventListener('DOMContentLoaded',function() {
document.querySelector("#yourGuess").onchange=check;
},false);
function check(event) {
if(event.target.value > 10 || event.target.value < 0){
alert("The number must be between 0 - 10");
event.target.value = 0;
}
}
<label for="yourGuess">You choose: </label>
<input id="yourGuess" type="number" min="0" max="10">
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