1、正则去空格

a.去掉字符串中所有空格

"   hello world   ".replace(/\s+/g,"");//helloworld

b.去掉字符串左边空格

var str = "   hello world   ".replace(/^\s*/g,"");//hello world..

c.去掉字符串右边空格

var str = "   hello world   ".replace(/\s*$/g,"");//...hello world

d.去掉字符串左边和右边空格

var str = "   hello world   ".replace(/(^\s*)|(\s*$)/g,"");//hello world

可以给String的原型添加方法

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,'');}

然后使用

"   hello world".LTrim();//hello world"hello world  ".RTrim();//hello world"  hello world  ".Trim();//hello world