textarea text change automatically detectected code example
Example 1: jquery detect change in textarea content
$('#textareaID').bind('input propertychange', function() {
$("#yourBtnID").hide();
if(this.value.length){
$("#yourBtnID").show();
}
});
Example 2: jquery detect textarea change
$('#myTextAreaID').on('input propertychange paste', function() {
//my Textarea content has changed
});