js脚本图片格式验证

function checkImgType(fileURL,strAlertMsg){    var Temp = false;    var right_type=new Array(".gif",".jpg",".jpeg",".png",".bmp");    var right_typeLen=right_type.length;    var imgUrl=fileURL.toLowerCase();    imgUrl=imgUrl.replace(/^(/s)*|(/s)*$/g,"");//去掉字符串两边的空格

    var postfixLen=imgUrl.length;    var len4=imgUrl.substring(postfixLen-4,postfixLen);    var len5=imgUrl.substring(postfixLen-5,postfixLen);     //判断是否是图片格式 for (i=0;i<right_typeLen;i++) {  if((len4==right_type[i])||(len5==right_type[i]))  {   Temp = true;  } } if (Temp == false) {  alert(strAlertMsg);  return false; } else {  return true; }

    }