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5 implementation methods and comparisons of js removing spaces before and after strings_javascript skills

WBOYOriginal: 2016-05-16 17:38:241236browse

If we write in the project that when the user enters spaces during registration, how do we remove the spaces?
The following is the js I often use to share with you:

The first type: Loop check and replace
[javascript]

Copy code The code is as follows:

 
//For users to call 
function trim(s){ 
return trimRight(trimLeft(s)); 
} 
//Remove the left blank 
function trimLeft( s){ 
if(s == null) { 
return ""; 
} 
var whitespace = new String(" tnr"); 
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 whitespace on the right www.jb51.net 
function trimRight(s){ 
if(s == null) return ""; 
var whitespace = new String(" tnr" ); 
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; 
} 

Second: regular replacement
[javascript]

Copy code The code is as follows:

Third method: use jquery
[javascript]

Copy code The code is as follows:

$.trim(str)

The internal implementation of jquery is:
[javascript]

Copy code The code is as follows:

 
function trim(str){ 
return str.replace(/^(s|u00A0) / ,'').replace(/(s|u00A0) $/,''); 
} 

The fourth way: use motorcycles
[javascript ]

Copy code The code is as follows:

 
function trim(str){ 
return str .replace(/^(s|xA0) |(s|xA0) $/g, ''); 
} 

The fifth way: cutting strings
[javascript]

Copy code The 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 is the most efficient when processing long strings.

Copy code The code is as follows: