How to limit the textarea to only hold numbers?

后端未结

关注

 6  635

I\'m trying to make a date textbox on my blog, and the date is only numbers. I don\'t want anybody making a mistake typing a letter. Is there any way to limit the characters

相关标签:

6条回答

滥情空心

2021-01-18 11:23
Yes, you need some JavaScript to do this. I found the JQuery date picker widget very useful to do exactly what you're wanting. The code that used to implement it is:

html to create the text field and not allow manual manipulation:
```
<input type="text" class="header_input" id="tvpostingdate" placeholder="Posting Date" default='' readonly="readonly">
```
the JS line binding the picker to the field with a specific format that my server side process is expecting:
```
$('#tvpostingdate').datepicker({ dateFormat: "mmddyy"});
```
You can find more information here: http://jqueryui.com/datepicker/
0 讨论(0)
发布评论:

提交评论
- 加载中...

没有蜡笔的小新

2021-01-18 11:27

Try this (utilizing jquery javascript library)

html

<input type="text" size="30" />

js (jquery library)

$(document).ready(function() {
    $("input").attr("placeholder", "Please input numbers").change(function(e) {
      var txt = /[a-z]/gi.test($(this).val());
      if (txt) {
        $(this).val("").attr("placeholder", "Not a number, please input numbers")
      };
    });
})

jsfiddle http://jsfiddle.net/guest271314/v2BRY/

Edit. Not certain if element is input ot textarea, hope should work for either.

javascript, without utilizing jquery javascript library

html

<input type="text" size="30" />

javascript

function checkText() {   
  var textarea = document.querySelectorAll("input");
  textarea[0].setAttribute("placeholder", "Please input numbers");    
  textarea[0].addEventListener("change", function(e) {
    var txt = /[a-z]/gi.test(e.target.value);
    if (txt) {
      e.target.value = "";
      e.target.setAttribute("placeholder", "Not a number, please input numbers");
    };    
  }, false);
};
checkText()

jsfiddle http://jsfiddle.net/guest271314/pFu4K/

Hope this helps

0 讨论(0)

情歌与酒

2021-01-18 11:27

You should use this function to set input filters on various DOM elements including textarea

function setInputFilter(textbox, inputFilter) {
        ["input", "keydown", "keyup", "mousedown", "mouseup", "select", "contextmenu", "drop"].forEach(function(event) {
            textbox.addEventListener(event, function() {
                if (inputFilter(this.value)) {
                    this.oldValue = this.value;
                    this.oldSelectionStart = this.selectionStart;
                    this.oldSelectionEnd = this.selectionEnd;
                } else if (this.hasOwnProperty("oldValue")) {
                    this.value = this.oldValue;
                    this.setSelectionRange(this.oldSelectionStart, this.oldSelectionEnd);
                } else {
                    this.value = "";
                }
            });
        });
    }

Then you simply set the filter, like that:

setInputFilter(document.getElementById("textarea_id"), value => {
        return /^\d*$/.test(value); // Allow digits and '.' only, using a RegExp
});

0 讨论(0)

不知归路

2021-01-18 11:34

you need some java script to implement this

<html>
<head>
<title>Test</title>
<script language="javascript">
function checkInput(ob) {
  var invalidChars = /[^0-9]/gi
  if(invalidChars.test(ob.value)) {
            ob.value = ob.value.replace(invalidChars,"");
      }
}
</script>
</head>

<body>
    <input type="text" onkeyup="checkInput(this)"/>
</body>
</html>

0 讨论(0)

北恋

2021-01-18 11:38
Use HTML5 input number type instead and leverage native browser validation. Thus, no JavaScript required.
```
<input type="number" />
```
It has wide support in browsers and it's the standard and best-practice solution.

Also on mobile and tablets the numeric key pad will appear instead.

See demo
0 讨论(0)
发布评论:

提交评论
- 加载中...

别跟我提以往

2021-01-18 11:41

If you use jQuery, you can do it like in this jsfiddle

$('input').keypress(function(e) {
    var a = [];
    var k = e.which;

    for (i = 48; i < 58; i++)
        a.push(i);

    if (!(a.indexOf(k)>=0))
        e.preventDefault();
});

0 讨论(0)