Select 3 to see the effect
<script> function Disablecheckbox () {var obj=document.getelementsbytagname ("Input") for (Var i=0;i<obj.lengt h;i++) {if (!obj[i].checked) obj[i].disabled = true; The function Ablecheckbox () {var obj=document.getelementsbytagname ("Input") for (Var i=0;i<obj.length;i++) Obj[i]. disabled = false; function check () {var obj=document.getelementsbytagname ("input") var sun=0; for (Var i=0;i<obj.length;i++) {if (obj[i].type== "checkbox" && obj[i].checked) sun++; if (sun< 3) {ablecheckbox (); Break else if (Sun = 3) {Disablecheckbox (); Event.srcelement.checked=true; Break else if (Sun > 3) {event.srcelement.checked=false; Break }} </script> <input type= ' checkbox ' name= ' cate[] ' value= ' 102 ' onclick= ' Check (); " > Cantonese <input type= ' checkbox ' name= ' cate[] ' value= ' onclick= ' "check ();" > Chaozhou <input type= ' checkbox ' name= ' cate[] ' value= ' onclick= ' "check ();" > Hakka <input type= ' checkbox' Name= ' cate[] ' value= ' onclick= ' check (); > Sichuan <input type= ' checkbox ' name= ' cate[] ' value= ' ' onclick= ' "check ();" > Shanghai/Jiangsu <input type= ' checkbox ' name= ' cate[] ' value= ' ' onclick= ' check (); > Hunan <input type= ' checkbox ' name= ' cate[] ' value= ' 108 ' onclick= ' Check (); " > Hubei <input type= ' checkbox ' name= ' cate[] ' value= ' 109 ' onclick= ' check (); " > Guizhou <input type= ' checkbox ' name= ' cate[] ' value= ' onclick= ' "check ();" > Northeast <input type= ' checkbox ' name= ' cate[] ' value= ' onclick= ' check (); > Jiangxi <input type= ' checkbox ' name= ' cate[] ' value= ' 112 ' onclick= ' Check (); " > Beijing <input type= ' checkbox ' name= ' cate[] ' value= ' 113 ' onclick= ' check (); " > Shandong <input type= ' checkbox ' name= ' cate[] ' value= ' 114 ' onclick= ' Check (); > Taiwan <input type= ' checkbox ' name= ' cate[] ' value= ' onclick= ' "check ();" > Xinjiang/Halal <input type= ' checkbox ' name= ' cate[] ' value= ' 116 ' onclick= ' Check (); " > Yunnan <input type= ' checkbox ' name= ' cate[] ' value= ' 117 ' onclick= ' Check ();"> Other Chinese Food <input type= ' checkbox ' name= ' cate[] ' value= ' 118 ' onclick= '" check (); " > Game <input type= ' checkbox ' name= ' cate[] ' value= ' 119 ' onclick= ' Check (); > hotpot <input type= ' checkbox ' name= ' cate[] ' value= ' onclick= ' "check ();" > Seafood <input type= ' checkbox ' name= ' cate[] ' value= ' 121 ' onclick= ' "check ();" > Pisa <input type= ' checkbox ' name= ' cate[] ' value= ' 122 ' onclick= ' "check ();" > Buffet <input type= ' checkbox ' name= ' cate[] ' value= ' 123 ' onclick= ' Check (); " > Tea Restaurant <input type= ' checkbox ' name= ' cate[] ' value= ' 124 ' onclick= ' check (); > Snack Pasta <input type= ' checkbox ' name= ' cate[] ' value= ' onclick= ' "check ();" > Barbecue <input type= ' checkbox ' name= ' cate[] ' value= ' 126 ' onclick= ' Check (); " > Vegetarian <input type= ' checkbox ' name= ' cate[] ' value= ' 127 ' onclick= ' Check (); " > Simple meal <input type= ' checkbox ' name= ' cate[] ' value= ' 128 ' onclick= ' Check (); > Fast food <input type= ' checkbox ' name= ' cate[] ' value= ' 129 ' onclick= ' check (); " > Bread Pastry <input type= ' checkbox ' Name= ' cate[] ' value= ' 130 ' onclick= ' check (); > Dessert <input type= ' checkbox ' name= ' cate[] ' value= ' 131 ' onclick= ' "check ();" > teahouse <input type= ' checkbox ' name= ' cate[] ' value= ' 132 ' onclick= ' check (); > Café <input type= ' checkbox ' name= ' cate[] ' value= ' ' onclick= ' "check ();" > Bar <input type= ' checkbox ' name= ' cate[] ' value= ' 134 ' onclick= ' Check (); " > Japan <input type= ' checkbox ' name= ' cate[] ' value= ' 135 ' onclick= ' check (); " > Korea <input type= ' checkbox ' name= ' cate[] ' value= ' 136 ' onclick= ' check (); " > Southeast Asia India <input type= ' checkbox ' name= ' cate[] ' value= ' 137 ' onclick= ' Check (); " > French <input type= ' checkbox ' name= ' cate[] ' value= ' 138 ' onclick= ' Check (); > Italian <input type= ' checkbox ' name= ' cate[] ' value= ' 139 ' onclick= ' Check (); > Latin <input type= ' checkbox ' name= ' cate[] ' value= ' 140 ' onclick= ' check (); > Borderless <input type= ' checkbox ' name= ' cate[] ' value= ' the ' onclick= ' () check (); > Western <input type= ' checkbox ' name= ' cate[] ' value= ' onclick= ' check (); > Other Western food
[Ctrl + A All SELECT Note: If the need to introduce external JS need to refresh to perform]
