Regex to check if http or https exists in the string

Try this:

function validateText(string) {
  if(/(http(s?)):\/\//i.test(string)) {
    // do something here
  }
}

From the looks of it, you're just checking if http or https exists in the string. Regular expressions are a bit overkill for that purpose. Try this simple code using indexOf:

function validateText(str)
{
    var tarea = str;
    if (tarea.indexOf("http://") == 0 || tarea.indexOf("https://") == 0) {
        // do something here
    }
}