如何减少前导空格和尾随空格

Question

var str = "    abcd    ";

if(str.match(/\ /)) { 
    document.writeln("String Empty");
} else {
    document.writeln("Length :  ");
    document.writeln(str.length);
}

The above code always returns an empty string although it has characters in between.

I need to chop the leading and trailing white spaces.

Answer 1

// Remove leading and trailing whitespace
// Requires jQuery
var str = " a b    c d e f g ";
var newStr = $.trim(str);
// "a b c d e f g"

// Remove leading and trailing whitespace
// JavaScript RegEx
var str = "   a b    c d e f g ";
var newStr = str.replace(/(^\s+|\s+$)/g,'');
// "a b c d e f g"

// Remove all whitespace
// JavaScript RegEx
var str = " a b    c d e   f g   ";
var newStr = str.replace(/\s+/g, '');
// "abcdefg"

Answer 2

Use trim and check the length:

if (!str.trim().length) { 
  document.writeln("String Empty");
}
else {
 document.writeln("Length : ");
 document.writeln(str.trim().length);
}