Function to chechk any changing in textbox and textarea:
$(document).on("keyup input","input:text, textarea", function(){
if(typeof $(this).attr('minlength') === 'undefined'){
var minLength = 1;
} else {
var minLength = $(this).attr('minlength');
}
if($(this).val().length >= minLength){
//do something
} else {
//do something
}
});