Implementation and comparison of five methods for removing spaces before and after strings in js

How can we remove spaces when users enter spaces during project registration?
Below is my frequently used js to share with you:

First: Replacement of cyclic check
[Javascript]
Copy codeThe Code is as follows:
// For the user to call
Function trim (s ){
Return trimRight (trimLeft (s ));
}
// Remove the left blank
Function trimLeft (s ){
If (s = null ){
Return "";
}
Var whitespace = new String ("\ t \ n \ r ");
Var str = new String (s );
If (whitespace. indexOf (str. charAt (0 ))! =-1 ){
Var j = 0, I = str. length;
While (j <I & whitespace. indexOf (str. charAt (j ))! =-1 ){
J ++;
}
Str = str. substring (j, I );
}
Return str;
}
// Remove the blank www.jb51.net on the right.
Function trimRight (s ){
If (s = null) return "";
Var whitespace = new String ("\ t \ n \ r ");
Var str = new String (s );
If (whitespace. indexOf (str. charAt (str. length-1 ))! =-1 ){
Var I = str. length-1;
While (I> = 0 & whitespace. indexOf (str. charAt (I ))! =-1 ){
I --;
}
Str = str. substring (0, I + 1 );
}
Return str;
}

Type 2: Regular Expression replacement
[Javascript]
Copy codeThe Code is as follows:
<Script language = "JavaScript">
<! --
String. prototype. Trim = function ()
{
Return this. replace (/(^ \ s *) | (\ s * $)/g ,"");
}
String. prototype. LTrim = function ()
{
Return this. replace (/(^ \ s *)/g ,"");
}
String. prototype. RTrim = function ()
{
Return this. replace (/(\ s * $)/g ,"");
}
// -->
</SCRIPT>

Third: Use jquery
[Javascript]
Copy codeThe Code is as follows:
$. Trim (str)

The internal implementation of jquery is:
[Javascript]
Copy codeThe Code is as follows:
Function trim (str ){
Return str. replace (/^ (\ s | \ u00A0) +/, ''). replace (/(\ s | \ u00A0) + $ /,'');
}

Type 4: Use motools
[Javascript]
Copy codeThe Code is as follows:
Function trim (str ){
Return str. replace (/^ (\ s | \ xA0) + | (\ s | \ xA0) + $/g ,'');
}

Method 5: Crop a string
[Javascript]
Copy codeThe Code is as follows:
Function trim (str ){
Str = str. replace (/^ (\ s | \ u00A0) + /,'');
For (var I = str. length-1; I> = 0; I --){
If (/\ S/. test (str. charAt (I ))){
Str = str. substring (0, I + 1 );
Break;
}
}
Return str;
}

After testing, the fifth method has the highest validity rate when processing long strings..
Copy codeThe Code is as follows:
<Script type = "text/JavaScript">
// Remove Spaces
Function SystemTrim (str ){
Var regExp =/(^ \ s *) | (\ s * $ )/;
Return str. replace (regExp ,"");
}
// Call
Function add ()
{
Var ownername = document. form1.ownername. value;
If (SystemTrim (ownername) = "")
{
Alert ("enter your name! ");
Return;
}
}
<Script>