使用javascript验证输入的字符量，文本长度和小数位 [英] Validate character amount, text length and decimal places from input using javascript

问题描述

我正在使用JavaScript来验证来自ASPxGridView控件(DevExpress组件)内部的文本框的输入.

I am using a javascript to validate input from a textbox that's inside a ASPxGridView control(DevExpress component).

我正在使用此javascript代码对其进行验证(通过OnKeyPress事件):

I am using this javascript code to validate it(thru OnKeyPress event):

function CheckKey(s, e) {
    var key = ASPxClientUtils.GetKeyCode(e.htmlEvent);
    var char = String.fromCharCode(key);
    if (e.htmlEvent.shiftKey) {
        if (!IsAvailableChar(char))
            ASPxClientUtils.PreventEvent(e.htmlEvent);
    } else
        if (!(IsAvailableChar(char) || IsAvailableKey(key))) ASPxClientUtils.PreventEvent(e.htmlEvent);

    return;
}

function IsAvailableChar(char) {
    var AvailableChars = "0123456789,";
    return AvailableChars.indexOf(char) != -1;
}

function IsAvailableKey(key) {

    switch (key) {
        case 46: //delete
            return true;
            break;
        case 37: //left arrow
            return true;
            break;
        case 39: //right arrow
            return true;
            break;
        case 16: //shift
            return true;
            break;
        case 188: //comma
            return true;
            break;
        default:
            return false;
            break;
    }

我使用它来阻止"某些字符，并且效果很好.但是，现在我想做一些更复杂的事情:我不希望用户在文本框中输入多个逗号.

I use this to "block" some characters and it works fine. But now I wanna do something a little bit more complicated: I don't want the user to input more than one comma in the textbox.

比这稍微复杂一点:此文本框的最大长度为6.我希望它仅允许两个小数位，并且最多允许三个数字在小数位前.例如:我希望它允许以下字符串:"123,12"，"45,32"，"7,65"，"9,6"，"85,32"，"94,1"，"310,2".我不希望它允许以下字符串:"1,123"，"125,789"，"1234,2"

A little bit more complicated than that: the maxlength of this textbox is 6. I want it to allow two decimal places only and the maximum of three numbers before the decimal places. For example: I want it to allow these strings: "123,12", "45,32", "7,65", "9,6", "85,32", "94,1", "310,2". I don't want it to allow these strings: "1,123", "125,789", "1234,2"

关于如何做到这一点的任何想法?

Any ideas on how I can do that?

谢谢！

我试图使用你们让我喜欢的两个正则表达式:

I tried to use the two regular expressions you guys told me to like this:

function CheckKey(s, e) {
    var key = ASPxClientUtils.GetKeyCode(e.htmlEvent);
    var char = String.fromCharCode(key);

    var text = document.getElementsByName(s.uniqueID)[0].value + char;

    var regEx = new RegExp("/^\d{0,3}(,\d{0,2})?$/");

    if(regEx.test(text))
        return;
    else
        ASPxClientUtils.PreventEvent(e.htmlEvent);

    return;
}

但是，即使输入与正则表达式匹配， regEx.test(text)始终返回false.

However, regEx.test(text) is always returning false, even when the input matches the regular expression.

另一项修改:

我从上面的代码中更改了RegExp对象的实例化:

I changed the instantiation of the RegExp object in the code above from this:

var regEx = new RegExp("/^\d{0,3}(,\d{0,2})?$/");

对此:

var regEx = /^\d{0,3}(,\d{0,2})?$/

现在可以了，谢谢！

推荐答案

/^\d{0,3}(,\d{0,2})?$/.test(textbox.value + char);

这将与最多三个小数位数匹配的任何数字匹配.(可选)它允许一个小数位和最多2个小数位.还匹配空字符串，以方便使用.因此，这将检查并确保结果框匹配.

This will match any number with as many as three pre-decimal places. Optionally, it allows a decimal and up to 2 decimal places. Also matches the empty string, for ease of use. So this will check to make sure the resultant box matches.

regEx的解释:

^

字符串开头

\d{0,3}

0至3位数字(含)

(...)? 

可选组

,\d{0,2}

逗号后跟0到2位数字(包括0和2位数字)

A comma followed by 0 to 2 digits (inclusive)

$

字符串的结尾.

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