为什么通过将变量与自身进行比较我的循环条件不起作用？

Question

var text = "dave kdfkdf dave kdfkdfffff dave";
var myName = "dave";
var hits = new Array();

var counter;
var nameCounter;


for (counter = 0; counter <= text.length; counter++){
    if (text[counter] === myName[0]) {
        for (nameCounter=counter; nameCounter < (nameCounter+myName.length); nameCounter++) {
            hits.push(text[nameCounter]);
        }
    }
}

the code above does not work, but when I change the condition of the second loop to:

nameCounter < (counter+myName.length);

then it does work.

can you explain, why? thanks :)

Answer 1

Simple math. I understand myName can be any name, with any length, but let's stick with "dave" and length of 4 and change myName.length to the hard-coded value of 4:

we're left with the following as the condition for your loop. it's never false, thus never stops*...

nameCounter < nameCounter + 4

*well, until it overflows, or run out of memory, etc.