文本框中的空白，制表符或空白的RegExp

Question

I need the help of the experts on this forum.

I would like to come up with a RegEx (javascript) to validate a textbox which has any blank spaces in it, any blank tabs in it, and also check for an empty textbox?

ie.

alert("Accepted")
------------------------------
Jameswithsometext
Billy Jean

alert("Not accepted")
------------------------------
- inadvertenly typed blank spaces
- inadvertenly typed tabs
- blank textbox

Answer 1

\\s should match any whitespace character. So if that's all there is, you have a problem.

var textbox = document.getElementById('mytextbox');
if (/^\s*$/.test(textbox.value)) {
  alert('Come on man, seriously, what the hell are you doing?');
} else {
  alert('Accepted');
}

See it here: http://jsfiddle.net/68KzX/

• ^ start of string
• \\s any whitespace character
• * match any number of characters
• $ end of string

So this will match if the string has zero characters, or if it has only whitespace characters.

Answer 2

Using /^\\S+$/ (at least one character of non-whitespace) we can do,

var p = prompt("Enter text", "");
var rx = /^\S+$/;
if (rx.test(p) == false)
    alert("Not accepted");
else
    alert("Accepted");

Note that this also handles the case of nothing entered.