jQuery Javascript - 在每次按键时从文本框中获取值

Javascript - get value from textbox at every keypress

提问by user2450099

I have a textbox and I want to use the data in it every time something is entered; letter by letter.

我有一个文本框，每次输入内容时我都想使用其中的数据；逐个字母。

What is happening is that when a value is entered, the Javascript is being executed beforethe value is actually put into the textbox, meaning that it always lags one character behind.

发生的情况是，当输入一个值时，Javascript 会在该值实际放入文本框之前执行，这意味着它总是落后一个字符。

$(document).ready(
      function() {
          $('#test').keypress(

          function() {
            var value = document.getElementById('test').value;
            alert(value);
          });
      })

<input id="test" type="text"  />

Here's whats happening:

这是发生了什么：

input alert
  w    ""
  e    "w"
  a    "we"
  l    "wea"
  t    "weal"
  h    "wealt"

Whereas I want it to happen dynamically; i.e. when I enter "w" I want the alert to contain "w" immediately after.

而我希望它动态发生；即当我输入“w”时，我希望警报立即包含“w”。

回答by dxh

keypresshappens before the change, yes. keyuphappens after. Listen to that instead.

keypress发生在更改之前，是的。keyup之后发生。听那个。

回答by Sergio

You should try keyupevent, because keypresshappens before symbol is being input in a textbox

您应该尝试keyup事件，因为keypress在文本框中输入符号之前发生

回答by Arun P Johny

use keyup

使用键盘

$(document).ready(
    function() {
        $('#test').keyup(
            function() {
                var value = document.getElementById('test').value;
                alert(value);
            });
    })

回答by John Dorean

Use keyupto read the valid after something has been entered. Here's how to do it with jQuery:

用于keyup在输入内容后读取有效值。下面是如何用 jQuery 做到这一点：

$(document).ready(function() {
    $('#test').keyup(function() {
        alert($(this).val());
    });
});

Demo

演示

回答by Vishal

use keyup instead that will work

使用 keyup 代替它会起作用

$(document).ready(
      function() {
          $('#test').keyup(

          function() {
            var value = document.getElementById('test').value;
            alert(value);
          });
      })

回答by Nicolae Olariu

Try using 'keyup' event instead of 'keypress'.

尝试使用“keyup”事件而不是“keypress”。

Change to:

改成：

$(document).ready(
      function() {
          $('#test').keyup(
          function() {
            var value = document.getElementById('test').value;
            alert(value);
          });
      });

Working plunk.

工作笨拙。

回答by Raoul George

Use the keyupevent instead -:

改用keyup事件 -：

         $('#test').keyup(    
           function() {
             var value = document.getElementById('test').value;
             alert(value);
          });

回答by IsisCode

Use keyupinstead, take a look at this:

使用keyup替代，看看这个：

http://jsfiddle.net/gEBc4/1/

http://jsfiddle.net/gEBc4/1/