Detect when input has a 'readonly' attribute

Since JQuery 1.6, always use .prop() Read why here: http://api.jquery.com/prop/

if($('input').prop('readonly')){ }

.prop() can also be used to set the property

$('input').prop('readonly',true);

$('input').prop('readonly',false);

what about javascript without jQuery ?

for any input that you can get with or without jQuery, just :

input.readOnly

note : mind camelCase

fastest way is to use the .is() jQuery function.

if ( $('input').is('[readonly]') ) { }

using [readonly] as a selector simply checks if the attribute is defined on your element. if you want to check for a value, you can use something like this instead:

if ( $('input').is('[readonly="somevalue"]') ) { }

Check the current value of your "readonly" attribute, if it's "false" (a string) or empty (undefined or "") then it's not readonly.

$('input').each(function() {
    var readonly = $(this).attr("readonly");
    if(readonly && readonly.toLowerCase()!=='false') { // this is readonly
        alert('this is a read only field');
    }
});