How to apply Watermark to TatxBox and iCheck plugin to CheckBox using jQuery in ASP.Net

hi

I use below code for changing checkbox appereance:

<script type="text/javascript">
    window.onload = function () {
        ApplyCss();
    };
    function ApplyCss() {
        $('input').iCheck({
            checkboxClass: 'icheckbox_square-red',
            radioClass: 'iradio_square-red',
            increaseArea: '20%' // optional
        });
    };
    //On PostBack
    var prm = Sys.WebForms.PageRequestManager.getInstance();
    if (prm != null) {
        prm.add_endRequest(function (sender, e) {
            if (sender._postBackSettings.panelsToUpdate != null) {
                ApplyCss();
            }
        });
    };

</script>

and below code for textbox's watermark:

<script type="text/javascript">
    window.onload = function SetColorOnPageLoad() {
        var defalutage = "مثال: 12 سال";
        //var defalutTaText = "تا";
        //var defalutsearch = "جستجو بر اساس کد ملک";
        functionSetColor(document.getElementById("Txtage"), defalutage);
        //functionSetColor(document.getElementById("Txtejare1"), defalutAzText);
        //functionSetColor(document.getElementById("Txtejare2"), defalutTaText);
        ApplyCss();
    }
 
    function functionSetColor(Textbox, WaterMark) {
 
        if (Textbox.value.length > 0 && Textbox.value == WaterMark) {
            Textbox.style.color = "#443f13";
            Textbox.style.fontSize = "13.5px";
 
        }
        else {
            Textbox.style.color = "white";
            Textbox.style.fontSize = "13.5px";
        }
    }
 
    function WaterMark(txt, evt, msg) {
 
        if (txt.value.length == 0 && evt.type == "blur") {
            txt.style.color = "#443f13";
            txt.value = msg;
            txt.style.fontSize = "13.5px";
            txt.style.fontfamily = "behtop_Yekan";
        }
 
        if (txt.value == msg && evt.type == "focus") {
            txt.style.color = "white";
            txt.value = "";
            if (txt.name == "Txtage") {
                txt.style.fontSize = "16px";
            }
            else {
                txt.style.fontSize = "13.5px";
            }
            txt.style.fontfamily = "behtop_Yekan";
        }
    }
 
    function ApplyCss() {
        $('select').selectric({
            maxHeight: 200
        });
    };
 
    var prm = Sys.WebForms.PageRequestManager.getInstance();
    if (prm != null) {
        prm.add_endRequest(function (sender, e) {
            if (sender._postBackSettings.panelsToUpdate != null) {
                ApplyCss();
            }
        });
    };
 
</script>

problem is when I use both code in page first code(for checkbox) doesn't work how I can use these two code together?

best regards

neda