title: Regex for two consecutive zero's at start of input
body: <p>I need to write regex expression which can disallow inputs to have two consecutive zeros at the start of input</p>
  
  <p>i've following regex rightnow
   /[^0-9]+/g 
  there is one issue with this, as it allows as many zeros at the start of input which is wrong, ideally i would like something which can allow one zero at start if user enters zero first followed by any numbers but no more zero at start so valid input should be 0,1, 01,099,100,10000000 , 980980567000 etc
  invalid input 00,001,00100,00100000 , 000087990432 etc</p>