Javascript verification can only enter numbers and a decimal point example_javascript skills

function gaga(obj){ // The value allows entering a decimal point and digits
obj.value = obj.value.replace(/[^d.]/g,""); //Replace all non-digits first, except numbers and.
obj.value = obj. value.replace(/^./g,""); //The first one must be a number instead of a number.
obj.value = obj.value.replace(/.{2,}/g,". "); // Ensure that only one appears, not multiple.
obj.value = obj.value.replace(".","$#$").replace(/./g,""). replace("$#$","."); //Guarantee. appears only once and cannot appear more than twice

}