通过javascript的requiredField验证器

问题描述：

大家好，我是javascript新手，请帮助我解决这个小问题.

Hi all, I am new with javascript please help me to solve this small problem..

how to make textbox required on buttonclick through javascript.

答

<!DOCTYPE html>
<html>
<head>
<script>
function validateNameInput()
{
	var value = document.getElementById('nameInput').value;
	if (value.length < 4)
		alert('String is too short. Must be 4 or more chars long\n\n(you used ' + value.length + ')');
	else
		alert('String valid\n\nLength: '+value.length);
}
</script>
</head>
<body>
	<label for='nameInput'>Enter a string - must be longer than 3 chars</label>
	<input id='nameInput' />
	<button onclick='validateNameInput();'>Validate</button>
</body>
</html>

此处是如何制作文本框必填字段的示例代码.

Here is a sample code of how to make a text box required field.

<asp:TextBox ID="Textbox1" runat="server"></asp:TextBox>
    <asp:Button ID="Button1" runat="server" Text="Button" OnClientClick="return ValidateTextBox()" />

<script type="text/javascript">
   function ValidateTextBox()
   {
       var Text = document.getElementById('<%=Textbox1.ClientID %>');

       if(Text.value == "")
       {
           alert('No data entered in textbox');
           return false;
       }

   }
   </script>

由于您不熟悉JavaScript，因此您可能会发现以下链接有用
JavaScript教程 [ ^ ]

初学者JavaScript [ ^ ]

Jquery教程 [ ^ ]

Since you are new to JavaScript you might find the below links useful
JavaScript Tutorial[^]

Beginner JavaScript[^]

Jquery Tutorial[^]

当我需要使用javascript进行任何操作时，我都使用jQuery(个人喜欢:))

因此，对于您的解决方案，我建议您使用jQuery.

请看下面的链接，
使用jQuery的RequiredFieldValidation [

Hi,

When anything i need to work with javascript, i use jQuery(personally i like it:))

So for your solution i would like to suggest you to use jQuery.

Please have a look at below link,
RequiredFieldValidation using jQuery[^]

Hope you enjoy working with jQuery.

Thanks
-Amit Gajjar

通过javascript的requiredField验证器

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