如何在jquery中检查文本字段中的空格

Question

I have a form. I want to put validation so that It will check if user enters white spaces or not. If its white spaces then show error. How could I do this?

Answer 1

In case you want to detect if there is any white space all through the user's input string,

var str = $("input").val();
if( str.indexOf(" ") !== -1 )
{
    alert("bad input");
}

Example: http://jsfiddle.net/pYquc/

Answer 2

Use jQuery.trim(str) which remove the whitespace or tabs and you can validate.

http://api.jquery.com/jQuery.trim/

Answer 3

function doValidations(){
   if(jQuery.trim( $(".className").val())==""){
     alert("error message");
     return false;    
   }else{
     return true;
   }
}

<input type="submit" onclick="return doValidations();">

Answer 4

Try this usong javascript:
var v = document.form.element.value;
var v1 = v.replace("","");
if( v1.length == 0){
 alert("error");
}

OR you can use following functions:

 // whitespace characters
      var whitespace = " \t\n\r";

      /****************************************************************/

      // Check whether string s is empty.
      function isEmpty(s)
      { return ((s == null) || (s.length == 0)) }

      /****************************************************************/

      function isWhitespace (s)
      {
           var i;

           // Is s empty?
           if (isEmpty(s)) return true;

           // Search through string's characters one by one
           // until we find a non-whitespace character.
           // When we do, return false; if we don't, return true.

           for (i = 0; i < s.length; i++)
           {
                // Check that current character isn't whitespace.
                var c = s.charAt(i);

                if (whitespace.indexOf(c) == -1) return false;
           }

           // All characters are whitespace.
           return true;
      }