String.prototype.trim = function(){
return this.replace(/(^\s*)|(\s*$)/g,‘‘);
}
例子：
var test = " abc ";
String.prototype.trim = function(){
return this.replace(/(^\s*)|(\s*$)/g,‘‘);
}
test = test.trim();
console.log(test);
原文：http://www.cnblogs.com/wongh/p/7670155.html