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javascriptvalidationisnullorempty

validation for empty or null input field

I need to check if the value of field patientid is empty or null and print an alert.

Somehow the code below is not working:

<td width="75">Patient ID<font color="red">*</font></td>
<td width="166"><form:input path="patientid"/></td>

Could you please help me out?

Solution

  • <form:input path="patientid"/> is not html.

    This should get you started:

    <td width="75">Patient ID<font color="red">*</font></td>
<td width="166"><input type="text" id="patientid" onchange="
   this.value==='' && alert( 'I am empty' );
"/></td>

    Or you could try to do this:

    <td width="75">Patient ID<font color="red">*</font></td>
<td width="166"><input type="text" id="patientid" onchange="
   this.value==='' && (this.value='I cannot be empty');
"/></td>