CODEWITHSUNDEEP
javascripthtmlvalidation
JLearner
JLearner

Reputation: 1311

Validation values

I'm trying to validate my values for alphabets and numberic as well as checking from database. I have created a function of validation and declaring my onclick button with validation function.

Function:

<script>
function validate()
{
var StudentID= document.getElementById('StudentID').value;
var StudentName = document.getElementById('StudentName').value;
    var StudentAdd = document.getElementById('StudentAdd').value;

    if(StudentID.length ==0 || StudentName.length ==0)
{
    alert("Please do not leave any blanks");
    return false;
}
else
{
            if(isNumeric(StudentID))
            { alert("correct") }
            else { alert("Numbers only!"); return false;}

    alert("Correct correct");   
}
    return true;
}
</script>

Sample Form:

<form id="Student" name="Student" method="post" action="nextpage.php">
<input name="StudentID" type="text" id="StudentID" value="<?php echo $StudentID?>"/>
<input name="StudentName" type="text" id="StudentName" value="<?php echo $StudentName?>"/>
<input name="StudentAdd" type="text" id="StudentAdd" value="<?php echo $StudentAdd?>"/>
<input type="submit" name="submit" value="Submit" onclick="return validate();"/>
</form>

I have already declared return validate function instead of calling my nextpage.php. But nothing popup for any alert. Kindly advise. Thanks

Upvotes: 0

Views: 1550

Answers (3)

Wern Ancheta
Wern Ancheta

Reputation: 23317

Try including your scripts after the body tag to make sure it only references elements after it has already been loaded. Then put return true inside the else statement.

function validate()
{
var StudentID= document.getElementById('StudentID').value;
var StudentName = document.getElementById('StudentName').value;
    var StudentAdd = document.getElementById('StudentAdd').value;

    if(StudentID.length ==0 || StudentName.length ==0)
{
    alert("Please do not leave any blanks");
    return false;
}
else
{
            if(isNumeric(StudentID))
            { alert("correct") }
            else { alert("Numbers only!"); return false;}

    alert("Correct correct");   
   return true;
}

}

Upvotes: 1

Lorenz
Lorenz

Reputation: 1313

There is no isNumeric() function in JavaScript (I get Uncaught ReferenceError: isNumeric is not defined). You have to create it on your own: Validate decimal numbers in JavaScript - IsNumeric()

Upvotes: 0

Robert
Robert

Reputation: 2471

Instead of the submit button's onclick, move the function to the form's onsubmit, like:

<form onsubmit="validate()" ...>

For the part of the 'if' statement that returns true you may run into some issues with the alerts() as the browser will be trying to submit the form, but over all it should work.

Upvotes: 0

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