js兑现repalceAll方法

js实现repalceAll方法

desc = "dd ggg ffff";String.prototype.replaceAll  = function(s1,s2){       return this.replace(new RegExp(s1,"gm"),s2);   alert(desc.replaceAll(' ',''));    }   

function checkform(){ if(document.form1.message.value==""||document.form1.message.value.replace(/(^\s*)|(\s*$)/g, "").length==0) {alert("不能发送空内容"); return false;} else return true; }