CODEWITHSUNDEEP
javascriptjquery
Pekka
Pekka

Reputation: 1115

Check input text value when page is loaded

I have a couple of register page in my project. Example is page to register student info, Enrolment Info,etc.

In the page I want to set button to disable when a criteria is met. This is my code

$(document).ready(function() { 

    if($('#student_id').val().length === 0){
        $('#student_update').prop( "disabled", true );
        $('#student_delete').prop( "disabled", true );
    }else{
        $('#student_add').prop( "disabled", true );
    }
});

If the student id is empty meaning there is nothing to update or delete I want to disable else the add button is disabled.

The Student Id is ready only meaning the only way to put value into it is to select data from database.

Upvotes: 0

Views: 2323

Answers (2)

Kurenai Kunai
Kurenai Kunai

Reputation: 1902

if( !$('#student_id').val() )

as you do not need to check if the length is > 0 since an empty string evaluates to false in jquery.

for readability you can use :

if( $('#student_id').val().length === 0 )

You can use something like this: 

$(document).ready(function() { 
    disableButton();
    $('#student_id').keyup(function(){  
    disableButton();
});
});

function disableButton(){
    if(!$('#student_id').val()){
        $('#student_update').prop( "disabled", true );
        $('#student_delete').prop( "disabled", true );
    $('#student_add').prop( "disabled", false);
    }else{
        $('#student_add').prop( "disabled", true );
    $('#student_update').prop( "disabled", false);
        $('#student_delete').prop( "disabled", false);
    }
}

Upvotes: 1

Brijesh Bhatt
Brijesh Bhatt

Reputation: 3830

Try this: 

if($('#student_id').val()=="")

OR spell lenght correctly:

if($('#student_id').val().length==0)

Upvotes: 1

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