使用Ajax提交表单是否安全？

So I have my form built in html and validated in JS and it does and looks the way I want. Now obviously I will be validating the input using PHP on the server side but I'm wondering if it would be secure enough to submit the form using Ajax and then validating on the server side, instead of submitting the form using a 'submit' type button and an 'action' attribute. Basically, is it safe to make server side validation dependent on the JS submitting it?So I have my form built in html and validated i