查找數組中匹配的字符（串）的位置

var StringValue = "Lorem ipsum dolor sit amet, consemctoretur elit";
var posotions = new Array();
var pos = StringValue.indexOf("em");

while(pos > -1){
	posotions.push(pos);
	pos = StringValue.indexOf("em", pos+1);
}

alert(posotions); // 3,32