如何使这个 JavaScript 与“严格使用”兼容？

Question

 window.onload = function() { init(); var date = new Date(); var dd = date.getDate(); var mm = date.getMonth() + 1; var yyyy = date.getFullYear(); //Add a zero if one Digit (eg: 05,09) if (dd < 10) { dd = "0" + dd; } //Add a zero if one Digit (eg: 05,09) if (mm < 10) { mm = "0" + mm; } minYear = yyyy - 80; //Calculate Minimun Age (<80) maxYear = yyyy - 15; //Calculate Maximum Age (>18) var min = minYear + "-" + mm + "-" + dd; var max = maxYear + "-" + mm + "-" + dd; document.getElementById("start").setAttribute("min", min); document.getElementById("start").setAttribute("max", max); };

I know the issue is that "minYear" and "maxYear" are undeclared variables, but I'm not sure how I'm meant to declare them without breaking the code entirely?

Answer 1

minYear and maxYear are variables like the others (date, dd, mm, etc...).

You should declare them using the "var " prefix, the first time you are using them.

var minYear = yyyy - 80;
var maxYear = yyyy - 15;