Javascript function that is equivalent for PHP function

2018-06-08 17:58:34

This question already has an answer here:

Validate decimal numbers in JavaScript - IsNumeric() 48 answers

Use regular expressions.

if (/-?d+(?:.d*)?(?:[eE][+-]?d+)?/.test(yourInput)) {
   // Do something
}

Of course, this will only work on strings. For a different method, see a duplicate question:

function isNumber(n) {
  return !isNaN(parseFloat(n)) && isFinite(n);
}

To only check if the input contains a number (0-9) at all, regex works again:

if (/[0-9]+/.test(yourInput)) {
   // Do something
}

如果所讨论的变量是$first_name

if( $first_name && !isNaN($first_name[0])) {

    // do something
}

在js中检查数字变量是否是一个数字：

isFinite(number) && !isNaN(parseFloat(number))

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