var A="abcd";
var B="1234abcdeard";
if(B.indexOf("abcd")!=-1){
alert("exsist!");
}else{
alert("not exsist!");
}
var B="1234abcdeard";
if(B.indexOf("abcd")!=-1){
alert("exsist!");
}else{
alert("not exsist!");
}
String.prototype.hasSubString=function(subStr)
{
var regx=new RegExp(subStr,'gi');//'g'区分大小写
return regx.test(this);
} var A="sdft";
var B="Abcfsdfd13j87";
alert(B.hasSubString(A));
</script>
A.indexOf(B)!=-1