i am using javascript for loop, to loop through a particular array and alert it's value. I want that after every alert it should stop for 30 seconds and then continue...till the end of loop. my code goes here..

    for(var i=0; i<valArray.lenght; i++)
    {
        alert("The value ="+valArray[i]);
        //stop for 30seconds..      
    }

i have used setTimeout() function, but it is not working...as loop end iterating but do not pause for 30seconds interval... is there any other way such as sleep function in PHP??