如何限制一个字段只能输入4个数字字符? [英] How to restrict a field to take only 4 numeric characters as input?
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问题描述
我想要一个文本字段只取数字和一些控制键,数字应该是四位数,而不是更少。我的验证码是
I wanted a text field to take only numbers ans some control keys and number should be exactly four digit long, not less not more. My validation code is
function checkValidInput()
{
$(".validateYearTextBox").keydown(function(event)
{
// Allow only delete, backspace,left arrow,right arraow and Tab
if (
event.keyCode == 46 //delete
|| event.keyCode == 8 //backspace
|| event.keyCode == 37 //leftarow
|| event.keyCode == 39 //rightarrow
|| event.keyCode == 9 //tab
)
{
// let it happen, don't do anything
}
else {
// Ensure that it is a number and stop the keypress
if ((event.keyCode < 48 || event.keyCode > 57) && (event.keyCode <96 ||event.keyCode > 105) ) {
event.preventDefault();
}
}
});
$(".validateYearTextBox").keyup(function(event)
{
var val = $(this).val();
if (val.length > 4){
alert ("Max length is 4");
val = val.substring(0, valore.length - 1);
$(this).val(val);
$(this).focus();
return false;
}
});
}
这里,我的第一次验证工作正常,但是我发送了一份不管用。
Here, my first validation is working, but my send one is not working.
我在我的aspx页面中调用此验证函数,如下所示
I am calling this validation function in my aspx page like this
<script type="text/javascript">
$(document).ready(function(){
checkValidInput();
}
</script>
出了什么问题?
推荐答案
简化它:
function checkValidInput() {
// Allow only delete, backspace, left arrow, right arrow,
// Tab, ctrl+v and numbers
$(".validateYearTextBox").keydown(function(event) {
if (!((event.keyCode == 46 ||
event.keyCode == 8 ||
event.keyCode == 37 ||
event.keyCode == 39 ||
event.keyCode == 9) ||
(event.ctrlKey && event.keyCode == 86) || // Edit: Added to allow ctrl+v
$(this).val().length < 4 &&
((event.keyCode >= 48 && event.keyCode <= 57) ||
(event.keyCode >= 96 && event.keyCode <= 105)))) {
// Stop the event
event.preventDefault();
return false;
}
});
// Edit: Added validate after copy+paste.
// This removes non-numeric characters and truncates the length
// to 4 if the user copy + pasted.
$(".validateYearTextBox").change(function(event) {
var value = $(this).val();
value = value.replace(/[^0-9]/g,'');
value = value.substr(0,4);
$(this).val(value);
});
}
$(document).ready(function() {
checkValidInput();
});
http://jsfiddle.net/nwellcome/687kD/
编辑:我个人喜欢蒙面输入 jQuery插件,但如果你需要做的话,这可能是一个严厉的解决方案。
Personally I like the Masked Input jQuery plugin but that might be a heavy-handed solution if this is all you need to do.
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