JSFiddle - React, Tailwind, and code Playground

by GregWoods

HTML

<form onsubmit="finalCheck(this)" method="post">
    <input name="aaa" value="1" /><br />
    <input name="bbb" value="" /><br />
    <input name="ccc" value="" /><br />
    <input name="ddd" value="4" /><br />
    <input type="submit" name="submit1" value="submit" /> 
</form>

JavaScript

function finalCheck(theForm) {
    var z = 0;
    for(var i=0;i<15;i++){
        var _i = theForm.elements[i].value;
        if(_i == ""){
            theForm.elements[i].style.background = '#FFD6D6';
            z = 1;
        }
    }
    if(z == 1){
        alert("Please correct the fields highlighted in red");
        return false;
    } else {
        return true;
    }

}