Javascript Trim Member Functions

function trim(stringToTrim) {
 return stringToTrim.replace(/^\s+|\s+$/g,"");
}
function ltrim(stringToTrim) {
 return stringToTrim.replace(/^\s+/,"");
}
function rtrim(stringToTrim) {
 return stringToTrim.replace(/\s+$/,"");
}

// example of using trim, ltrim, and rtrim
var myString = " hello my name is ";
alert("*"+trim(myString)+"*");
alert("*"+ltrim(myString)+"*");
alert("*"+rtrim(myString)+"*");

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function ltrim(str) { 
 for(var k = 0; k < str.length && isWhitespace(str.charAt(k)); k++);
 return str.substring(k, str.length);
}
function rtrim(str) {
 for(var j=str.length-1; j>=0 && isWhitespace(str.charAt(j)) ; j--) ;
 return str.substring(0,j+1);
}
function trim(str) {
 return ltrim(rtrim(str));
}
function isWhitespace(charToCheck) {
 var whitespaceChars = " \t\n\r\f";
 return (whitespaceChars.indexOf(charToCheck) != -1);
}