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I am checking if the user input is left empty or not using my check like that:

function myFunction() {
    if(nI.value.length<1)
    {
        alert("Field is empty!"); 
        return false; 
    }
    else 
    {   
        return true; 
    }
}

where nI is the text input object.

I read in another place we can do that through:

function isSignificant( text ){
  var notWhitespaceTestRegex = /[^\s]{1,}/;
  return String(text).search(notWhitespaceTestRegex) != -1;
}

The last function is checking for whitespace. What is the difference between checking for empty string and whitespace?

I am checking if the user input is left empty or not using my check like that:

function myFunction() {
    if(nI.value.length<1)
    {
        alert("Field is empty!"); 
        return false; 
    }
    else 
    {   
        return true; 
    }
}

where nI is the text input object.

I read in another place we can do that through:

function isSignificant( text ){
  var notWhitespaceTestRegex = /[^\s]{1,}/;
  return String(text).search(notWhitespaceTestRegex) != -1;
}

The last function is checking for whitespace. What is the difference between checking for empty string and whitespace?

• javascript
• html

Share Improve this question Follow edited Oct 24, 2016 at 7:40 William asked Oct 6, 2016 at 3:13 WilliamWilliam 33022 gold badges1010 silver badges2323 bronze badges 4

• First check if string length is not zero. This also considers a single space ` ` as valid string. Second, checks if there is at-least one non-space character. – Tushar Commented Oct 6, 2016 at 3:15
• 2 The second test makes the first redundant, it would be simpler as /\S/.test(nI.value). ;-) – RobG Commented Oct 6, 2016 at 3:19
• @Tushar not sure what u mean – William Commented Oct 6, 2016 at 3:20
• if(nI.value.trim()) will work... trim() removes space on each end and an empty string is falsy – charlietfl Commented Oct 6, 2016 at 3:25

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1 Answer 1

Sorted by: Reset to default 6

First you should know the difference between empty string and a white space.

The length of a white ' ' space is 1 .

An empty string '' will have a length zero.

If you need to remove any number of white spaces at both starting and ending of a string you may use trim() function, then you may count the length if it is necessary.

OR

You may check for empty string after using trim()

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