Question

How can I apply this trim function: var trimmed = str.replace(/^\s+|\s+$/g, '') ; to this code below so that if a textbox contains whitespaces, it will display message “Incorrect”? Also If I use this function am I able to use “/” in the textbox because the textbox may contain data with “/”.

  if (moduletext.value == ""){
      errmsg.innerHTML = "Incorrect";
    }else{
            errmsg.innerHTML = "Correct"; 
    }  

Answer 1

The easiest way to do what you’re trying to do is check the trimmed value’s length.

var trimmed = moduletext.value.replace(/^\s+/, '').replace(/\s+$/, '');
if(!trimmed.length) {
  errmsg.innerHTML = 'Incorrect';
} else {
  errmsg.innerHTML = 'Correct';
}

If you know what browser you’re using (generally anything not <IE9), you may be able to use the native browser implementation of trim, i.e. 'my string'.trim();