javascript 将输入字段限制为一位小数点和两位小数
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Limiting input field to one decimal point and two decimal places
提问by Jonah
I have an input field which is limited to 6 characters. How can I validate my input field so that a user can't put more than one decimal point (i.e. 19..12), plus it can only be to two decimal places as well (i.e. 19.123)?
我有一个限制为 6 个字符的输入字段。如何验证我的输入字段，以便用户不能输入超过一个小数点（即 19..12），而且它也只能保留两位小数（即 19.123）？
This is my input field
这是我的输入字段
<input type="text" name="amount" id="amount" maxlength="6" autocomplete="off"/><span class="paymentalert" style="color:red;"></span>
Here is my validation script.
这是我的验证脚本。
$(function(){
$("#amount").keypress( function(e) {
var chr = String.fromCharCode(e.which);
if (".1234567890NOABC".indexOf(chr) < 0)
return false;
});
});
$("#amount").blur(function() {
var amount = parseFloat($(this).val());
if (amount) {
if (amount < 40 || amount > 200) {
$("span.paymentalert").html("Your payment must be between ￡40 and ￡200");
} else {
$("span.paymentalert").html("");
}
} else {
$("span.paymentalert").html("Your payment must be a number");
}
});
Jonah
约拿
回答by Denys Séguret
This should do :
这应该做：
var ok = /^\d*\.?\d{0,2}$/.test(input);
(if I correctly understood that you don't want more than 2 digits after the dot)
（如果我正确理解您不希望点后超过 2 位数字）
The code thus would be :
因此，代码将是：
$("#amount").blur(function() {
var input = $(this).val();
if (/^\d*\.?\d{0,2}$/.test(input)) {
var amount = parseFloat(input);
if (amount < 40 || amount > 200) {
$("span.paymentalert").html("Your payment must be between ￡40 and ￡200");
} else {
$("span.paymentalert").html("");
}
} else {
$("span.paymentalert").html("Your payment must be a number");
}
});
回答by talemyn
Assuming that:
假如说：
- There MUST have 2 digits after a decimal point, and
- There must be at least 2 digits before the decimal point, but no more than 3 digits
- 小数点后必须有 2 位数字，并且
- 小数点前必须至少有2位数字，但不能超过3位数字
The code you would use to match it would be:
你用来匹配它的代码是：
var value = $(this).val;
value.match(/^\d{2,3}(\.\d{2})?$/i);
回答by Michael H?rtl
It would be much easier if you used the Masked Input Pluginfor jQuery.
如果您使用jQuery的Masked Input Plugin会容易得多。
