<!DOCTYPE html> <html lang="en"> <head> <meta charset="UTF-8"> <title>Title</title> <style> .gg{ color:#dddddd; (浅灰色) } .bb{ color:black; (黑色的字体) } </style> </head> <body> <input type="text" class="gg" value="请输入内容" onfocus="Focus(this);" onblur="Blur(this);"/> <script> function Focus(ths){ //查找第一种方式 //document //第二种方式 (this) //ths ths.className = "bb"; var current_val = ths.value; if(current_val == "请输入内容"){ ths.value = "" } } function Blur(ths){ var current_val = ths.value; if(current_val == "请输入内容" || current_val.trim().length == 0){ ths.value = "请输入内容"; ths.className == "gg"; } } </script> </body>
原文：http://www.cnblogs.com/wuyongcong/p/5658926.html
