Implementation Method of removing spaces before and after strings in js, and implementation of spaces in js strings

Implementation Method of removing spaces before and after strings in js, and implementation of spaces in js strings

When we edit some pages, spaces before and after the string are usually invalid. Therefore, you must filter the information.

For example:

　　Input: [Space] [space] a [space] B [space] [space] [space]

　　Get: A [space] B

The Code is as follows:
Remove leading space

function LTrim(str){   var i;   for(i=0;i<str.length;i++){    if(str.charAt(i)!=" ")       break;   }   str = str.substring(i,str.length);   return str; }

Remove Spaces

function RTrim(str){   var i;   for(i=str.length-1;i>=0;i--){     if(str.charAt(i)!=" ")       break;   }   str = str.substring(0,i+1);   return str; }

Usage

function Trim(str){    return LTrim(RTrim(str));  }

[Recommended] Regular Expression

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, ""); } 

Add other methods:

First: Replacement of cyclic check

// 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 white space on the right. www.jb51.net 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 ;}

Method 2: Crop a string

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; } 

The above is a variety of methods for js to remove spaces before and after strings. I hope this will be helpful for your learning.

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