Javascipt มี Concat มั้ยครับ เขียนยังไงรับค่ามาจาก php

function add()
{
	var Qty1=parseInt(document.forms.form1.txtQty1.value);
	if (document.forms.form1.txtQty1.value === "")
	{
		Qty1=0;
	}
	var Qty2=parseInt(document.forms.form1.txtQty2.value);
	if (document.forms.form1.txtQty2.value === "")
	{
		Qty2=0;
	}
	var Qty3=parseInt(document.forms.form1.txtQty3.value);
	if (document.forms.form1.txtQty3.value === "")
	{
		Qty3=0;
	}
	var Qty4=parseInt(document.forms.form1.txtQty4.value);
	if (document.forms.form1.txtQty4.value === "")
	{
		Qty4=0;
	}
	var amount = Qty1+Qty2+Qty3+Qty4;
	document.forms.form1.amount.value=amount;


	var pri1=Qty1*22000;
	var pri2=Qty2*15000;
	var pri3=Qty3*7500;
	var pri4=Qty4*100000;
	var tot = parseFloat(pri1+pri2+pri3+pri4);
	document.forms.form1.tot.value=tot.toFixed(2);
	document.forms.form1.pri1.value=pri1;
	document.forms.form1.pri2.value=pri2;
	document.forms.form1.pri3.value=pri3;
	document.forms.form1.pri4.value=pri4;


	

}

function add()
{
	for(i=1;i<=100;i++)
		{
			var Qty[i]=parseInt(document.forms.form1.txtQty+i.value);
			if (document.forms.form1.txtQty+i.value === "")
			{
				Qty[i]=0;
			}
		}
	/*var Qty2=parseInt(document.forms.form1.txtQty2.value);
	if (document.forms.form1.txtQty2.value === "")
	{
		Qty2=0;
	}
	var Qty3=parseInt(document.forms.form1.txtQty3.value);
	if (document.forms.form1.txtQty3.value === "")
	{
		Qty3=0;
	}
	var Qty4=parseInt(document.forms.form1.txtQty4.value);
	if (document.forms.form1.txtQty4.value === "")
	{
		Qty4=0;
	}*/
	var amount = Qty[1]+Qty[2]+Qty[3]+Qty[4];
	document.forms.form1.amount.value=amount;
		

	var pri1=Qty[1]*22000;
	var pri2=Qty[2]*15000;
	var pri3=Qty[3]*7500;
	var pri4=Qty[4]*100000;
	var tot = parseFloat(pri1+pri2+pri3+pri4);
	document.forms.form1.tot.value=tot.toFixed(2);
	document.forms.form1.pri1.value=pri1;
	document.forms.form1.pri2.value=pri2;
	document.forms.form1.pri3.value=pri3;
	document.forms.form1.pri4.value=pri4;

<td align="center"><input name="txtQty<?=$i;?>" type="text" id="txtQty<?=$i;?>" size="15" value="" onChange ="add()" onkeyup="digitsOnly(this);doCalSum(<?=$i;?>,this.value,<?=$objResult["PRO_Price"];?>)"></td>	
		<td align="center"><span name="spnSum<?=$i;?>" id="spnSum<?=$i;?>">$0.00</span>
		<input type="hidden" name="hdnSum<?=$i;?>" id="hdnSum<?=$i;?>" value="" ></td>
		<input type="hidden" name="pri<?=$i;?>" id="pri<?=$i;?>" value="pri<?=$i;?>"></td>
		<input type="hidden" name="proid<?=$i;?>" id="proid<?=$i;?>" value="<?=$objResult["PRO_ID"];?>" ></td>
		<input type="hidden" name="stock<?=$i;?>" id="stock<?=$i;?>" value="<?=$objResult["PRO_Stock"];?>" ></td>
		<input type="hidden" name="proname<?=$i;?>" id="proname<?=$i;?>" value="<?=$objResult["PRO_Name"];?>" ></td>
		<input type="hidden" name="proprice<?=$i;?>" id="proprice<?=$i;?>" value="<?=$objResult["PRO_Price"];?>" ></td>

                for(i=1;i<=4;i++)
		{
			var Qty[i]=parseInt(document.getElementById("txtQty"+i).value);
			if (document.getElementById("txtQty"+i).value == "")
			{
				Qty[i]=0;
			}
		}

for(i=1;i<=100;i++)
		{
			var Qty[i]=parseInt(document.getElementById("txtQty"+i).value);
			if (document.getElementById("txtQty"+i).value === "")
			{
				Qty[i]=0;
			}
		}

vfunction add()
{
	var Qty = new Array();
	for(i=1;i<=9;i++)
		{
			Qty[i]=parseInt(document.getElementById("txtQty"+i).value);
			if (document.getElementById("txtQty"+i).value === "")
			{
				Qty[i]=0;
			}
		}

	var amount = Qty[1]+Qty[2]+Qty[3]+Qty[4]+Qty[5]+Qty[6]+Qty[7]+Qty[8]+Qty[9];
	document.forms.form1.amount.value=amount;
}

function add()
{
	var Qty = new Array();
        var amount;
	for(i=1;i<=9;i++)
		{
			Qty[i]=parseInt(document.getElementById("txtQty"+i).value);
			if (document.getElementById("txtQty"+i).value === "")
			{
				Qty[i]=0;
			}
		

	amount += Qty[i];
	document.forms.form1.amount.value=amount;
                  }
}