Delete first character of string if it is 0

You can remove the first character of a string using substring:

var s1 = "foobar";
var s2 = s1.substring(1);
alert(s2); // shows "oobar"

To remove all 0’s at the start of the string:

var s = "0000test";
while(s.charAt(0) === '0')
{
 s = s.substring(1);
}