javascript regex for password containing at least 8 characters, 1 number, 1 upper and 1 lowercase [duplicate]

Your regular expression should look like:

/^(?=.*\d)(?=.*[a-z])(?=.*[A-Z])[0-9a-zA-Z]{8,}$/

Here is an explanation:

/^  (?=.*\d)          // should contain at least one digit  (?=.*[a-z])       // should contain at least one lower case  (?=.*[A-Z])       // should contain at least one upper case  [a-zA-Z0-9]{8,}   // should contain at least 8 from the mentioned characters$/

Using individual regular expressions to test the different parts would be considerably easier than trying to get one single regular expression to cover all of them. It also makes it easier to add or remove validation criteria.

Note, also, that your usage of .filter() was incorrect; it will always return a jQuery object (which is considered truthy in JavaScript). Personally, I'd use an .each() loop to iterate over all of the inputs, and report individual pass/fail statuses. Something like the below:

$(".buttonClick").click(function () {    $("input[type=text]").each(function () {        var validated =  true;        if(this.value.length < 8)            validated = false;        if(!/\d/.test(this.value))            validated = false;        if(!/[a-z]/.test(this.value))            validated = false;        if(!/[A-Z]/.test(this.value))            validated = false;        if(/[^0-9a-zA-Z]/.test(this.value))            validated = false;        $('div').text(validated ? "pass" : "fail");        // use DOM traversal to select the correct div for this input above    });});

Working demo

At least 8 = {8,}:

str.match(/^(?=.*[0-9])(?=.*[a-z])(?=.*[A-Z])([a-zA-Z0-9]{8,})$/)