If parseInt is used inside the 'for' loop, it works for all cases. But in this example, it is not working properly for cases like 99-100 or 999-1000. What happens here? Is the implicit conversion wrong?

function buggy10000(value)
{
    var r = value.split("-");
    var len=r.length;
    var j;
    if(len==2)
    {
        console.log("For in RANGE " + r[0]+"<-->"+r[1]);
        for(j=r[0];j<=r[1];j++)
        {
            console.log(j);
        }
    }

}

buggy10000("98-99");
buggy10000("99-100");  //for not working as expected
buggy10000("100-102");

• javascript

because: "98" <= "99" (string comparison)

"100" <= "102"

but "99" > "100"

The conversion appears only when j++ is called, but for the second case (99-100) that never happens, because the loop condition fails.

function buggy10000(value)
{
    var r = value.split("-");
    var len=r.length;
    var j;
    if(len==2)
    {
        console.log("For in RANGE " + r[0]+"<-->"+r[1]);
        for(j=r[0]*1;j<=r[1]*1;j++) <----Modified
        {
            console.log(j);
        }
    }

}

Does it work?

This is a type conversion problem, and it's related to comparisons. You're passing strings to your function, splitting the string, then comparing them. JS is getting confused as you're comparing strings, not integers.

I rewrote your function as follows to explicitly parse those values as integers, and it's working as you expect now.

function buggy10000(value)
{
    var r = value.split("-");
    var len=r.length;
    var j;
    if(len==2)
    {
        console.log("For in RANGE " + r[0]+"<-->"+r[1]);
        r[0] = parseInt(r[0]);
        r[1] = parseInt(r[1]);
        for(j=r[0];j<=r[1];j++)
        {
            console.log(j);
        }
    }

}