JS determines whether the input is a number and how many decimal places to retain-JS Tutorial-php.cn

JS determines whether the input is a number and how many decimal places to retain

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Release： 2018-05-22 14:12:19

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This time I will bring you JS to determine whether the input is a number and how many decimals to retain. JS to determine whether the input is a number and how many decimals to retain. What are the precautions?. Here is a practical case. One Get up and take a look.

1. Verification method validationNumber(e, num) e represents the label object, num represents the number of decimal places to be retained

function validationNumber(e, num) {
      var regu = /^[0-9]+\.?[0-9]*$/;
      if (e.value != "") {
        if (!regu.test(e.value)) {
          alert("请输入正确的数字");
          e.value = e.value.substring(0, e.value.length - 1);
          e.focus();
        } else {
          if (num == 0) {
            if (e.value.indexOf('.') > -1) {
              e.value = e.value.substring(0, e.value.length - 1);
              e.focus();
            }
          }
          if (e.value.indexOf('.') > -1) {
            if (e.value.split('.')[1].length > num) {
              e.value = e.value.substring(0, e.value.length - 1);
              e.focus();
            }
          }
        }
      }
    }

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2. Verification integer

<asp:TextBox ID="txtNg" name="txtNg" runat="server" Height="16px" Width="98px" Font-Size="9pt"
   CssClass="EditTextBox" onpropertychange="validationNumber(this,0)"></asp:TextBox>

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3. One digit is reserved Decimal

<asp:TextBox ID="txtChglinecost" name="txtChglinecost" runat="server" Height="16px" Width="98px" Font-Size="9pt" 
   CssClass="EditTextBox" onpropertychange="validationNumber(this,1)"></asp:TextBox>

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4. Keep two decimal places

<asp:TextBox ID="txtStdyr" name="txtStdyr" runat="server" Height="16px" Width="98px" Font-Size="9pt" 
   CssClass="EditTextBox" onpropertychange="validationNumber(this,2)"></asp:TextBox>

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5. Keep three decimal places

Just put validationNumber(this,3) in the method Just change the second parameter to 3.

Keep four decimal places, keep five decimal places, and so on...

I believe you have mastered the method after reading the case in this article. For more exciting information, please pay attention to other related articles on the PHP Chinese website !