为什么我的javascript无法正常工作？ javascript应该接受数字chararcters，退格键或删除键 [英] why does my javascript not working? the javascript should accept numeric chararcters, backspace or delete key

问题描述

这是我的javascript：

Here's my javascript:

function numeric(evt) {
        var charCode = (evt.which) ? evt.which : event.keyCode
        var keyCodeEntered = (event.which) ?
                             event.which :
                             (window.event.keyCode) ?
                                 window.event.keyCode :
                                 -1;
        if (charCode > 31 && ((charCode >= 48 && charCode <= 57) || charCode == 46 || keyCodeEntered == 8))
            return true;
        else {
            alert('Please Enter Numeric values.');
            return false;
        }
    }

我在这里使用它：

I use it here:

<asp:TextBox ID="txtStartSY" runat="server" Width="200px" maxlength="4"
        onkeyup="compute(this.value);"
        onfocus="if (this.value == 'Enter start of school year') this.value = '';"
        onblur="if (this.value == '') this.value = 'Enter start of school year';"
        value="Enter start of school year" style="color:Gray; text-align:left;"
        xmlns:asp="#unknown" ontextchanged="txtStartSY_TextChanged" onkeypress="return numeric(event)" />

推荐答案

使用FilteredTextBoxExtender以下是示例代码

Use FilteredTextBoxExtender Here is sample code

<asp:TextBox ID="txtRentalPeriodPoint" runat="server" CssClass="fromborder" Width="75"

                                                   MaxLength="3"></asp:TextBox>
                                               <ajaxToolkit:FilteredTextBoxExtender ID="FilteredTextBoxExtender6" runat="server"

                                                   TargetControlID="txtRentalPeriodPoint" FilterType="Numbers" Enabled="True" />

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